The Concept of Theosis in Early Patristic Thought: A Hermeneutical Perspective ()
I. Introduction: Theosis in Early Christian Thought
The doctrine of theosis, understood as human participation in the divine life, occupies a central position in early patristic theology. While it was later systematized within Byzantine and Eastern Orthodox traditions, its conceptual foundations are evident in the exegetical and theological reflections of early Christian thinkers. Among these, Irenaeus of Lyons (c. 130-202) and Gregory of Nyssa (c. 335-395) provide two distinct yet complementary models of theosis, shaped by their respective hermeneutical methodologies, doctrinal commitments, and historical contexts.
Irenaeus of Lyons develops his vision of theosis within the framework of recapitulation (ἀνακεφαλαίωσις), a theological construct in which Christ, as the New Adam, restores and perfects human nature by retracing and redeeming the history of the fall (Adversus Haereses (hereafter AH), V.21.1; Behr, 2013: p. 175). This restoration is both ontological and eschatological: the incarnate Logos does not merely heal human nature but elevates it to divine communion, culminating in an eschatological transformation (AH, III.19.1; Steenberg, 2009: p. 73). Irenaeus’s exegetical method is predominantly typological, presenting salvation history as a unified and teleological movement, in which Christ fulfills and restores the divine image lost in Adam (Behr, 2000: p. 45). Theosis, in this framework, is not an abstract mystical ascent but a historically grounded process, realized through Christ’s work and participation in the Church’s sacramental life (AH, V.2.3).
Gregory of Nyssa, by contrast, articulates a more apophatic and dynamic vision of theosis, grounded in his doctrine of infinite ascent (ἡ συνεχὴς προκοπή). While Irenaeus envisions deification as historical restoration and fulfillment in Christ, Gregory argues that true participation in God is inherently unending, since the divine essence is infinite and incomprehensible (De Vita Moysis, II.239). His hermeneutical approach is shaped by the allegorical tradition, particularly in his interpretation of Moses’ ascent on Mount Sinai (Exod. 33:20), which he reads as a symbol of the soul’s ceaseless progress into divine mystery (Vita Moysis, II.231; Daniélou, 1944: p. 193). Unlike Irenaeus, who sees theosis as the completion of divine participation through Christ, Gregory envisions an eternal journey, in which perfection is never a static state but a continuous transformation (In Ecclesiasten Homiliae, VIII; Ladner, 1959: p. 98).
Despite their theological and exegetical differences, both Irenaeus and Gregory affirm theosis as a dynamic and participatory process rather than a mere ontological elevation. While Irenaeus grounds transformation within the historical and eschatological framework of Christ’s recapitulation, Gregory envisions it as an infinite ascent into the divine abyss.
This study undertakes a comparative theological analysis of Irenaeus and Gregory of Nyssa, attending closely to the hermeneutical methods, scriptural engagements, and doctrinal frameworks through which each articulates theosis. Rather than viewing their models as contradictory—one emphasizing historical restoration, the other mystical progression—this paper argues that their divergent emphases reflect a shared commitment to the transformative nature of salvation. By examining the theological architecture that undergirds their respective visions, this study seeks to show that Irenaeus and Gregory, when placed in dialogue, reveal a unified trajectory of deification: one that is inaugurated through Christ’s incarnational work and perpetually expanded through the soul’s deepening participation in divine life.
2. Scriptural Roots of Theosis: Divergent Readings
The doctrine of theosis, though fully developed in patristic theology, is firmly rooted in key biblical passages that emphasize humanity’s participation in the divine life. Both Irenaeus of Lyons and Gregory of Nyssa engage with these texts, yet their interpretations diverge in ways that reflect their broader theological frameworks. Irenaeus, following a historical and typological approach, understands theosis as the restoration of the divine image through Christ’s redemptive work. Gregory, by contrast, employs an allegorical and mystical exegesis, viewing theosis as an unending ascent toward divine perfection. Despite these differences, both theologians affirm that deification is not an instantaneous transformation but a dynamic and unfolding process rooted in Scripture.
1) The Imago Dei (Genesis 1:26)—Creation, corruption, and restoration
“Then God said, ‘Let us make man in our image, after our likeness.’”
The doctrine of the imago Dei forms the foundation of both Irenaeus’s and Gregory’s conceptions of theosis, yet they approach its significance differently. For Irenaeus, the distinction between image (εἰκών) and likeness (ὁμοίωσις) is crucial to his theological anthropology. He argues that humanity was created in the image of God, but full participation in divine life, represented by the notion of likeness, was meant to be realized through growth, obedience, and maturation. The fall did not erase this divine image but distorted it, necessitating restoration through Christ’s recapitulation (AH, V.6.1). The Incarnation, then, serves as the means by which the divine likeness is reestablished, with Christ retracing and redeeming the history of human disobedience, ultimately leading humanity to its intended participation in God (AH, III.19.1). For Irenaeus, then, theosis is not a speculative mystical ascent but a concrete historical process, one that is realized through Christ’s redemptive work and extended to believers through the sacraments (AH, V.2.3). Gregory of Nyssa, however, also affirms that humanity bears the divine image, yet he departs from Irenaeus in viewing theosis as an open-ended process with no fixed point of completion. Rather than seeing divine likeness as something that is simply restored, Gregory envisions it as an infinite potential that can never be exhausted. While the fall introduced corruption into human nature, it did not merely distort the divine image but created a rupture that necessitates continual transcendence toward God (Vita Moysis, II.239; Daniélou, 1944: p. 201). Because God is infinite and beyond all comprehension, the soul’s participation in divine life is likewise never-ending (In Ecclesiasten Homiliae, VIII). Whereas Irenaeus sees theosis as a historical return to an original divine state, Gregory conceives of it as an eternal progression into an ever-deepening divine likeness.
2) Psalm 82:6 and John 10:34—Deification as divine sonship
“I said, ‘You are gods, and all of you are sons of the Most High.’”
This passage, later echoed in John 10:34, is one of the strongest scriptural affirmations of theosis and is frequently cited in patristic writings. However, while both Irenaeus and Gregory invoke this passage, their interpretations differ significantly. Irenaeus situates Psalm 82:6 within his broader framework of recapitulation, arguing that humanity was always meant to be divinized but only through participation in Christ, the true Son of God. Theosis, therefore, is not an innate human capacity but a grace-filled transformation, made possible through the Incarnation (AH, III.6.1). According to Irenaeus, Christ’s recapitulation of human history restores humanity’s divine destiny, enabling believers to become partakers of the divine life (AH, V.21.1). Theosis, in this sense, is not a natural human right but a gift received through Christ’s mediation and participation in the sacramental life of the Church (AH, V.2.3). In contrast, Gregory of Nyssa uses this passage to emphasize the soul’s progressive ascent into divine life, interpreting it as an affirmation that human nature is called to an infinite process of transformation. Rather than seeing deification as a completed event in Christ, he understands it as a continual deepening of divine participation. Theosis, then, is not simply about regaining a lost status but about unceasing movement into greater union with God (Oratio Catechetica, XXVI). This distinction between a fulfilled reality in Christ (Irenaeus) and an open-ended process of infinite ascent (Gregory) reflects the fundamental difference between their respective models of deification.
3) 2 Peter 1:4—Participation in divine nature as fulfillment vs. process
“He has granted to us His precious and magnificent promises, so that by them you may become partakers of the divine nature.”
This passage from 2 Peter is perhaps the most explicit biblical articulation of theosis, and both Irenaeus and Gregory engage with it to support their respective theological visions. Irenaeus reads this verse within the framework of recapitulation, understanding it as an affirmation that Christ took on human nature so that humanity might partake in the divine nature (AH, V.2.3). For him, theosis is not merely an abstract concept but an event anchored in salvation history, accomplished through Christ’s Incarnation and continued through the life of the Church (AH, III.22.4). Participation in the divine nature, therefore, is something that occurs within the historical economy of salvation, as Christ’s work restores humanity to its original divine communion. Gregory of Nyssa, on the other hand, sees this passage as a powerful confirmation of his doctrine of infinite ascent. Because God’s nature is infinite, Gregory argues that participation in the divine nature must also be infinite; there can be no final state of completion, only perpetual progress (De Beatitudinibus, VI). Even in eternity, theosis does not reach an end but continues indefinitely, as the human soul is always capable of greater union with God (Contra Eunomium, III.7). While Irenaeus understands 2 Peter 1:4 as an eschatological fulfillment of deification in Christ, Gregory sees it as an indication that divine participation is never fully exhausted, but rather an eternal movement toward the infinite divine mystery (Daniélou, 1944: p. 203).
Although Irenaeus and Gregory of Nyssa approach the doctrine of theosis through distinct theological and hermeneutical lenses, both affirm that deification is not a static event but an unfolding journey of transformation. For Irenaeus, Scripture testifies to a historical and Christocentric pattern in which the divine plan for humanity is fulfilled through Christ’s redemptive work—recapitulating Adam and restoring the image of God through participation in the incarnate Logos. Gregory, by contrast, reads the same scriptural texts as invitations into mystery, using allegory and apophatic theology to portray theosis as an infinite deepening of divine participation that transcends temporal boundaries. Though their methods diverge—typology versus allegory, historical realization versus eternal progression—their goal converges: a restored and ever-deepening communion with the divine. Rather than presenting rival soteriologies, their insights offer complementary vistas on the same mystery. Theosis emerges here as both realized in history and infinitely open-ended: a process that begins with Christ but finds no final terminus, continually drawing the human soul into the boundless life of God.
3. Irenaeus of Lyons: Theosis through Christ’s Restorative
Work
1) Christ as the New Adam: Healing and Recapitulation
For Irenaeus of Lyons, theosis is inseparable from his doctrine of recapitulation (ἀνακεφαλαίωσις), the idea that Christ, as the New Adam, restores and completes humanity’s original divine destiny. Rooted in Paul’s Adam-Christ typology (Romans 5:12-21; 1 Corinthians 15:22, 45) and Ephesians 1:10, Irenaeus envisions salvation as a progressive unfolding of God’s plan, culminating in the Incarnation. He argues that humanity, created in God’s image, fell from divine communion through sin, and Christ’s work reverses this fall, reintegrating human nature into divine life (AH, V.21.1). Unlike later mystical traditions that emphasize individual spiritual ascent, Irenaeus presents theosis as a historical and communal reality—a transformation accomplished through Christ and extended to all humanity (AH, III.19.1; Behr, 2013: p. 175). In this vision, the divine likeness, lost in Adam, is restored through Christ’s Incarnation and redemptive work. This idea is perhaps best encapsulated in his famous formula: “Our Lord Jesus Christ, through His transcendent love, became what we are, that He might bring us to be even what He is Himself” (AH, V.Preface).1 Irenaeus’s language here is not merely poetic but doctrinal: by assuming the fullness of human nature, Christ reconfigures humanity’s trajectory, uniting creaturely life with the divine. This is not a symbolic elevation, but an ontological reconstitution. As he explains elsewhere, “He passed through every stage of life, sanctifying each in turn... so that He might be the perfect teacher for all ages, and sanctify all humanity” (AH II.22.4). In this view, deification is not abstract metaphysics—it is the historical healing and reformation of human nature through the incarnate Christ. While later theologians, including Gregory of Nyssa, would expand on the theme of deification, Irenaeus frames it primarily as a historical-redemptive event rather than an ongoing mystical journey. His emphasis on the Incarnation as the definitive turning point in salvation history distinguishes his theology from later speculative interpretations of theosis (Steenberg, 2009: p. 73).
2) Typology and Theosis: Salvation as Fulfillment
Irenaeus’s method of biblical interpretation is primarily typological, in contrast to the allegorical readings that would later dominate Alexandrian theology. Unlike Origen and Gregory of Nyssa, who sought hidden mystical meanings in Scripture, Irenaeus views biblical history as a unified, teleological narrative, culminating in Christ. His exegesis follows Paul’s Adam-Christ parallel, wherein Christ recapitulates and perfects what was lost in Adam, restoring humanity’s divine vocation (AH, III.22.4; Russell, 2004: p. 109).
Irenaeus’s typology is particularly evident in his reading of Genesis 1:26 and Romans 5:12-21, where he interprets Adam as the archetype of fallen humanity and Christ as the New Adam who restores what was lost. According to Irenaeus, Adam was created in the image of God, yet he failed to attain divine likeness due to sin. The Fall introduced corruption into human nature, necessitating the Incarnation as the act of recapitulation in which Christ retraces and perfects human existence. Humanity’s original telos was always participation in divine life, yet it could only be fully realized through Christ, who gathers all things in Himself (Ephesians 1:10). This historical and eschatological dimension of Irenaeus’s thought sets him apart from later theological perspectives, which often emphasize deification as an individual mystical ascent rather than a corporate reality anchored in the Incarnation (Behr, 2000: p. 47).
Irenaeus also invokes Psalm 82:6 and 2 Peter 1:4 to support his vision of theosis, but he rejects any notion that human beings can attain divinity by nature. While both Irenaeus and Gregory of Nyssa cite these passages in defense of deification, their readings differ substantially. Irenaeus insists that theosis is only possible through participation in Christ’s redemptive work; it is not a natural human capacity but a grace-filled transformation granted through the Incarnation (AH, III.6.1). Unlike Gregory, who emphasizes an eternal deepening of divine participation, Irenaeus frames theosis as a completed reality within Christ’s historical work. In this regard, his theology remains firmly tied to the economy of salvation rather than speculative metaphysical ascent (Steenberg, 2009: p. 91).
3) Sacrament and Church: Participating in the Restored Divine Image
A crucial aspect of Irenaeus’s doctrine of theosis is that it is not an individualistic mystical ascent but a corporate reality—humanity as a whole is restored through Christ. The Incarnation is not merely a moral transformation or an abstract metaphysical union with God but a concrete participation in Christ’s incarnate life. For Irenaeus, the divine image in humanity was damaged by sin, but in Christ, it is restored and perfected (AH, III.22.4). This transformation does not occur through intellectual contemplation or mystical effort but through participation in the sacramental life of the Church, which is the extension of Christ’s presence in the world.
The role of the Church and the Eucharist is central to Irenaeus’s understanding of theosis. Unlike later theological models that emphasize individual mystical experience, Irenaeus grounds deification in the ecclesial and sacramental economy. He maintains that the Eucharist is the means through which believers participate in divine life, as it unites them to the glorified body of Christ2. Irenaeus connects theosis directly to the Eucharist as the vehicle of Christ’s transformative presence. He writes, “How can they say that the flesh is incapable of receiving the gift of God, which is eternal life, when it is nourished by the body and blood of the Lord, and is a member of Him?” (AH V.2.3). Here, deification is sacramentally embodied: the flesh, once subject to corruption, becomes the site of divine participation through communion with Christ’s glorified body. “Our flesh, when it receives the Eucharist, is no longer corruptible, having the hope of the resurrection to eternity” (AH, V.2.3). This sacramental theology reinforces Irenaeus’s insistence that theosis is not an abstract or esoteric pursuit but a tangible, communal, and embodied transformation (Behr, 2013: p. 182).
4) The Difference Between Irenaeus and Gregory of Nyssa
While both Irenaeus and Gregory affirm theosis, their models differ significantly in emphasis. Irenaeus envisions theosis as a completed restoration through Christ, while Gregory sees it as an infinite, unending ascent toward divine mystery. Irenaeus’s theology is firmly historical, rooted in the Incarnation as the decisive moment of human restoration, whereas Gregory adopts a more mystical approach, emphasizing humanity’s eternal movement toward God. Their hermeneutical differences further highlight this contrast: Irenaeus relies on typology and salvation history, interpreting Christ as the fulfillment of divine promises, while Gregory employs allegory and mystical symbolism, seeing human destiny as an unceasing journey into divine transcendence.
Nevertheless, despite these differences, both theologians uphold theosis as a process-oriented transformation rather than an instantaneous state. The key distinction lies in how this process unfolds—for Irenaeus, theosis is fulfilled in Christ’s Incarnation and mediated through the Church, while for Gregory, it extends into eternity as an infinite ascent into divine mystery.
Irenaeus’s concept of recapitulation remains foundational for later Christian theology, influencing figures such as Athanasius, the Cappadocians, and Maximus the Confessor. His emphasis on Christ as the means of theosis, his rejection of Gnostic dualism, and his use of typology shaped the trajectory of patristic thought on deification. However, his insistence on a historically fulfilled theosis contrasts with later mystical traditions, particularly that of Gregory of Nyssa, who sees theosis as an infinite ascent into divine mystery. Rather than opposing views, these models of theosis can be understood as complementary dimensions of human participation in the divine life—Irenaeus provides the historical and Christocentric foundation, while Gregory expands it into the eternal journey of the soul toward God. While Irenaeus provides a Christocentric and sacramental foundation for the doctrine of theosis—anchoring deification within the historical arc of salvation—his vision does not exhaust the mystery of divine participation. To grasp the full breadth of early patristic thought on deification, we must now turn to Gregory of Nyssa, whose mystical theology of infinite ascent expands the horizons of theosis beyond historical restoration into the realm of eternal transformation. In the following section, Gregory’s vision will be explored in dialogue with Irenaeus’s typological framework, revealing how both thinkers contribute essential dimensions to a unified theology of deification.
4. Gregory of Nyssa: Theosis as Eternal Ascent
1) Beyond Restoration: The Soul’s Infinite Journey into God
For Gregory of Nyssa, theosis is not merely the restoration of a lost divine state, as Irenaeus suggests, but rather a perpetual movement toward God that has no final completion. Unlike Irenaeus, who views theosis as fulfilled in Christ’s redemptive work, Gregory envisions it as an eternal process—an ascent that never ceases, because God’s infinite and incomprehensible nature ensures that divine participation is inexhaustible (Vita Moysis, II.239). This doctrine, often referred to as epéktasis3 (ἡ συνεχὴς προκοπή), frames human perfection not as a static state but as a continuous becoming. Since divine perfection is boundless, the human soul, created in the image of God, must always move beyond itself, striving for an ever-greater participation in divine life.
This vision is best articulated in Gregory’s Life of Moses, where he describes the journey of Moses as an allegory for the soul’s infinite ascent toward God. He writes, “The one who ascends never stops ascending, and the one who runs toward the Lord never reaches the end of the journey” (Vita Moysis, II.239). Unlike Irenaeus, who sees theosis as a return to divine communion lost through sin, Gregory insists that deification is a process without end, since the closer one draws to God, the more one realizes the infinite distance that remains (In Ecclesiasten Homiliae, VIII; Ladner, 1959: p. 101). Gregory expresses this most vividly in The Life of Moses, where he writes, “The one who ascends never ceases to go from beginning to beginning, by beginnings that never end” (Vita Moysis II.239). Divine perfection, he argues, is not something the soul finally possesses but continually pursues, precisely because “true vision consists in seeing that the divine nature is invisible” (ibid. II.231). Theosis, in this context, is not the arrival at a final goal, but the perpetual renewal of desire for the divine. Whereas Irenaeus frames salvation history as a movement toward fulfillment in Christ, Gregory views human destiny as an eternal progression into divine mystery. This distinction underscores Gregory’s unique contribution to patristic theology: theosis is not merely about reclaiming what was lost but about continuously deepening participation in God’s infinite life.
2) Allegory and Theosis: Moses as the Paradigm of Transformation
Gregory’s approach to biblical interpretation differs significantly from that of Irenaeus. While Irenaeus employs a historical and typological method, viewing salvation history as a unified movement toward fulfillment in Christ, Gregory follows the allegorical tradition of Origen, reading Scripture as a symbolic representation of the soul’s spiritual transformation. His exegesis of Exodus 33:20, Philippians 3:12-14, and 2 Peter 1:4 demonstrates his commitment to this mystical hermeneutic, in which biblical figures and narratives serve as paradigms for the soul’s journey into deeper divine participation (Daniélou, 1944: p. 198).
In his interpretation of Exodus 33:20, where God tells Moses, “You cannot see My face, for no one can see Me and live,” Gregory sees this passage as emblematic of theosis itself. He argues that divine union is never fully attained but is always pursued. The closer one comes to God, the more one realizes that God remains beyond all comprehension (Vita Moysis, II.231). Unlike Irenaeus, who sees the Incarnation as the definitive moment in which God is revealed to humanity, Gregory insists that true knowledge of God consists in realizing that there is always more to know. This reflects his commitment to apophatic theology—the idea that God is ultimately unknowable and that the highest form of divine knowledge is recognizing one’s own ignorance (Contra Eunomium, III.6).
Gregory’s reading of Philippians 3:12-14 further illustrates his view that human perfection is an ongoing process rather than a completed state. When Paul states, “Not that I have already obtained it or have already become perfect, but I press on,” Gregory sees this as scriptural confirmation that theosis is never finalized but always progressing (De Beatitudinibus, VI). Unlike Irenaeus, who situates the fulfillment of theosis within the historical economy of salvation, Gregory insists that even in eternity, theosis continues, as divine perfection can never be fully grasped.
His interpretation of 2 Peter 1:4, which declares that believers are called to become “partakers of the divine nature,” further confirms this doctrine of infinite ascent. Gregory argues that since God’s nature is infinite, participation in the divine nature must also be infinite (Contra Eunomium, III.7). Unlike Irenaeus, who reads this passage as affirming the restoration of humanity’s divine vocation in Christ, Gregory sees it as indicating that deification is a never-ending process. This distinction marks one of the most significant differences between their models of theosis: for Irenaeus, deification has an eschatological fulfillment in Christ, while for Gregory, divine participation is never fully exhausted but extends into eternity (Daniélou, 1944: p. 203).
3) The Limitlessness of Divine Participation: Can Perfection Ever Be Attained?
The most striking feature of Gregory’s model of theosis is his insistence that divine union is not a static state but a perpetual transformation. Unlike Irenaeus, who envisions deification as the restoration of humanity to its original divine likeness, Gregory insists that even in its perfected state, the human soul will never cease growing in divine life. Since God’s nature is infinite, theosis must also be infinite; union with God can never be fully achieved, but it can always deepen (Vita Moysis, II.239). In this sense, Gregory shifts the focus of theosis from fulfillment to progress, from restoration to endless ascent.
He expresses this idea most clearly in his doctrine of epéktasis, or the soul’s unceasing movement toward God. “The perfection of human nature consists in its very growth in goodness,” he writes, suggesting that perfection is not a final condition but an ongoing process of transformation (Vita Moysis, II.225). Unlike Irenaeus, who situates theosis within a definitive Christocentric framework, Gregory opens the doctrine to an eschatological horizon that never reaches completion. In Contra Eunomium, Gregory insists that even in the afterlife, the soul’s longing is not satisfied by stasis but animated by divine inexhaustibility: “The soul becomes ever greater by its ongoing participation, yet it never reaches the limit of the good things it seeks” (Contra Eunomium III.5). For Gregory, transformation is endless not because of human deficiency, but because of God’s infinite plenitude4. Theosis thus reflects not human inadequacy, but divine generosity. For him, divine perfection is not something that can be attained but something that must be eternally pursued.
4) Implications of Gregory’s Thought: Theosis as Eternal Ascent
Gregory’s theology of infinite ascent presents a direct challenge to static views of salvation, including those that conceive of deification as a singular moment of transformation. Unlike Irenaeus, who emphasizes a historical and sacramental framework for theosis, Gregory argues that salvation is an ongoing deepening of divine participation. This perspective has significant theological implications: it shifts the focus from a past event to a continuous process, emphasizing that human perfection is never complete but is always unfolding (In Ecclesiasten Homiliae, VIII).
Moreover, Gregory’s model of theosis reshapes the eschatological vision of the Christian life. If divine participation is never fully realized, then even in the afterlife, the soul remains in a state of growth and transformation. This idea departs from Irenaeus’s more historical view of deification as something fulfilled in Christ. Instead, Gregory suggests that salvation is not about returning to a lost state but about progressing into divine fullness. Theosis, in this sense, is not just a historical reality but an eternal movement beyond history, into God’s infinite being (Contra Eunomium, III.6; Daniélou, 1944: p. 203).
Gregory of Nyssa fundamentally transforms the doctrine of theosis by shifting it from a completed restoration to an eternal movement toward God. While Irenaeus sees theosis as the fulfillment of humanity’s divine vocation through Christ’s work, Gregory expands the concept into an unceasing mystical ascent. This theological innovation has profound implications, particularly in its emphasis on divine infinitude and the eternal progression of the soul. Whereas Irenaeus situates theosis within the framework of salvation history, Gregory extends it beyond time itself, portraying human destiny as an endless journey into divine mystery.
Rather than viewing these two models as conflicting, they can be understood as complementary. Irenaeus provides the historical foundation for theosis, grounding it in Christ’s recapitulation, while Gregory develops its eschatological implications, showing that divine participation is always deepening. Gregory’s vision of unending ascent into divine mystery offers a powerful complement to Irenaeus’s historical and sacramental theology of recapitulation. Taken together, their models press us to ask: can theosis be both fulfilled in Christ and eternally unfinished? This question forms the heart of the following section, where their respective theological frameworks will be brought into dialogue—not to collapse their differences, but to uncover how these two voices, in their tension and resonance, illuminate a more expansive vision of human participation in the divine.
5. Convergence and Theological Implications
1) Two Paths to Theosis: Fulfillment vs. Endless Becoming?
At first glance, Irenaeus of Lyons and Gregory of Nyssa seem to present two contrasting models of theosis. Irenaeus emphasizes theosis as a historical restoration, culminating in Christ’s recapitulation of humanity, while Gregory envisions it as an unending mystical ascent in which no final perfection is ever reached. These differences, however, do not necessarily indicate a fundamental opposition. Rather, their theological frameworks offer two perspectives on the same transformative process—one grounded in salvation history and the other in the infinite nature of divine participation. By examining their respective understandings of theosis in light of their hermeneutical methodologies, doctrinal commitments, and theological emphases, it becomes clear that Irenaeus and Gregory share a fundamental vision of deification as a dynamic process rather than a static event. Although they differ in their depictions of how theosis unfolds, their views are not contradictory but complementary, revealing two stages in the unfolding mystery of divine participation.
2) Where They Agree: Christocentrism, Divine Participation, and Grace
Despite their theological and hermeneutical differences, both Irenaeus and Gregory affirm three core convictions about theosis. First, they both reject the idea that theosis is an instantaneous event and instead emphasize its unfolding nature. For Irenaeus, theosis is realized through Christ’s recapitulation, which restores human nature and initiates a process of transformation that culminates in divine communion. Gregory likewise emphasizes that deification is never complete but is always progressing toward deeper participation in the divine. Although Irenaeus sees theosis as being fulfilled in Christ’s redemptive work and Gregory envisions it as an eternal ascent, both stress that theosis is an ongoing process rather than a momentary transformation.
Second, both theologians uphold the Christocentric nature of theosis, affirming that human participation in divine life is only possible through Christ. Irenaeus grounds theosis in Christ’s recapitulation, arguing that through the Incarnation, Christ restores humanity to divine communion. Gregory, while emphasizing the infinite nature of deification, also maintains that theosis is initiated through Christ, who opens the path for unending ascent into divine life. This shared Christological foundation ensures that neither theologian envisions theosis as an autonomous process independent of divine grace. Instead, both recognize that deification is fundamentally mediated through the person of Christ.
Third, Irenaeus and Gregory both emphasize that theosis involves active human participation in divine life. While they differ in their interpretations of how this participation unfolds, neither theologian sees theosis as something passively received. Irenaeus emphasizes participation in Christ’s redemptive work through the sacramental life of the Church, particularly in baptism and the Eucharist. Gregory, in contrast, underscores the soul’s ongoing striving toward deeper union with God. Despite these differences, both insist that deification is not an automatic process but one that requires continual cooperation with divine grace. This shared conviction reinforces their broader agreement that theosis is a transformative process rather than a static state.
3) Key Differences: Typology vs. Allegory, History vs. Infinity
Although they share a process-oriented vision of theosis, Irenaeus and Gregory differ significantly in their theological emphases and hermeneutical approaches. Irenaeus understands theosis as Christocentric recapitulation, in which the Incarnation restores humanity’s divine vocation. His biblical exegesis is rooted in typology, wherein Christ fulfills and perfects salvation history, gathering all things in Himself (Ephesians 1:10). Theosis, in this framework, is a historical and eschatological reality, made possible through Christ’s redemptive work. Gregory, on the other hand, sees theosis as an eternal ascent, in which the soul perpetually deepens its participation in the divine mystery. His approach to Scripture is primarily allegorical, with figures like Moses serving as symbols of the soul’s unending movement toward God. For Gregory, divine perfection is inexhaustible, and thus, theosis has no final fulfillment.
These differences reflect two distinct theological paradigms. Irenaeus emphasizes fulfillment and completion in Christ, seeing theosis as a historical reality that is fully realized in Christ’s recapitulation. Gregory, in contrast, highlights continual transformation, arguing that because God is infinite, participation in divine life must also be infinite. This distinction leads to their differing eschatological visions: Irenaeus sees theosis as something achieved within salvation history, whereas Gregory situates it beyond history, as an eternal process that continues indefinitely.
4) Bridging the Gap: Irenaeus as the Foundation, Gregory as the Continuation
Rather than viewing these two models of theosis as contradictory, they can be understood as two stages of the same theological vision. Irenaeus provides the historical and Christological foundation for deification, grounding it in Christ’s recapitulation and the sacramental life of the Church. His theology ensures that theosis is not an abstract or speculative concept but a concrete reality realized in history. Gregory, building upon this foundation, extends theosis into eternity, highlighting the unceasing nature of divine participation. If Irenaeus presents theosis as a restoration of humanity’s divine calling, Gregory expands it into an eschatological vision of endless ascent. Together, they offer a unified model in which theosis begins with Christ’s redemptive work but is never fully exhausted, as human nature remains eternally capable of deeper participation in the divine.
By integrating these perspectives, theosis can be understood as a reality that is both fulfilled in Christ and open-ended in its continual realization. This synthesis provides a richer understanding of deification—one that recognizes both the historical grounding of theosis in salvation history and its infinite unfolding in the life of the believer. Far from being opposed, these two theological frameworks complement one another, demonstrating that theosis is at once historical and eschatological, complete in Christ yet always expanding in its infinite potential.
5) Reconsidering Salvation: Not Just Return, But Ever-Deepening Union
Bringing Irenaeus’s and Gregory of Nyssa’s visions of theosis into dialogue yields important insights for contemporary theological reflection, particularly in the domains of soteriology, scriptural interpretation, and ecumenical engagement. At its core, their shared emphasis on deification as a transformative journey contests reductive models of salvation that focus solely on juridical justification—where righteousness is imputed rather than embodied. In contrast, both theologians underscore that salvation entails an actual participation in the divine life, a process that unfolds over time and engages the whole person. This reframing shifts theological attention away from forensic categories alone and toward a participatory, relational dynamic in which the believer is gradually conformed to God’s likeness through grace. Such a perspective not only deepens the Church’s understanding of human destiny but also invites renewed exploration of salvation as both historical and experiential, communal and mystical.
Second, the juxtaposition of Irenaeus’s and Gregory’s theological models underscores the enduring relevance of both historical and mystical modes of engaging the doctrine of theosis. Irenaeus, through his typological reading of Scripture, presents salvation as the culmination of a divinely orchestrated narrative, one in which the Incarnation restores and completes the divine intention embedded in creation. In contrast, Gregory’s allegorical and apophatic hermeneutic opens up a more contemplative dimension—one in which Scripture points not only to historical fulfillment but to the soul’s unending pilgrimage into divine mystery. Rather than privileging one mode over the other, a mature theological framework will draw upon both: honoring the concrete, historical specificity of God’s redemptive action while also embracing the infinite horizon of transformation that continues beyond time. This dual lens allows theosis to be understood not as a doctrinal abstraction, but as a lived mystery that continually unfolds within the Church and the soul alike.
Finally, the convergence of Irenaeus’s and Gregory’s perspectives offers fertile ground for ecumenical dialogue. While theosis has long been emphasized within Eastern Orthodox theology, Irenaeus’s deeply Christocentric and sacramental vision reveals that the concept is not alien to the Western tradition but rooted in early catholic thought. Gregory’s mystical elaboration, far from being exclusively ‘Eastern,’ resonates with contemplative strands found in Western figures such as Augustine or Bernard of Clairvaux. When these historical and mystical currents are brought together, they invite a broader theological synthesis—one that affirms theosis as a shared inheritance rather than a point of division. Such integration not only enriches doctrinal reflection but also opens new possibilities for communion across longstanding confessional boundaries5. Recognizing the complementary nature of Irenaeus’s and Gregory’s models allows for a broader engagement with the doctrine of deification across different Christian traditions.
Rather than being two conflicting models, Irenaeus and Gregory together offer a unified theological vision of theosis. Theosis is both a historical reality and an eternal journey—rooted in Christ’s work, yet infinitely expansive in its unfolding. The human journey toward God is both complete in Christ and yet infinitely deepening in divine participation. This integrated vision provides a richer, more dynamic understanding of salvation—one that bridges past and present, East and West, history and mystery. Their theological insights, when brought into dialogue, enrich the Christian understanding of deification, revealing it as a transformative process that unfolds within salvation history yet never reaches a final limit in its movement toward divine life.
6. Conclusion: Rethinking Theosis in Light of Patristic
Thought
1) The significance of historical vs. mystical models of theosis
This study has examined the theological and hermeneutical foundations of theosis in the thought of Irenaeus of Lyons and Gregory of Nyssa, identifying both their differences and points of convergence. For Irenaeus, theosis is inextricably bound to the doctrine of recapitulation: Christ, as the New Adam, retraces the trajectory of fallen humanity, healing and perfecting human nature by restoring it to its original divine orientation. Created in the image of God, humanity was destined for likeness through obedience and growth, yet sin introduced rupture and distortion. Through the Incarnation, Christ assumes the fullness of human life, recapitulates its history, and realigns it with the divine will, thereby enabling humanity to be restored, not merely to its original state, but to a higher participation in the divine life through union with the incarnate Logos. His theology is deeply historical, rooted in a typological reading of Scripture, in which Christ fulfills the divine plan by reversing Adam’s failure and leading humanity back to divine communion (AH, III.22.4; Behr, 2013: p. 175). Theosis, in this framework, is a concrete and historical transformation, mediated through Christ and the sacramental life of the Church, particularly through baptism and the Eucharist. In contrast, Gregory of Nyssa envisions theosis not as a return to an original state, but as an open-ended ascent into the inexhaustible mystery of God, whose infinite being renders complete union perpetually elusive. For Gregory, the soul’s participation in the divine does not culminate in finality but unfolds as a ceaseless motion—what he terms epéktasis—where each step toward God reveals yet another horizon, precisely because divine plenitude can never be fully grasped or possessed. Theosis, in this view, is not a static possession of divinity but an ever-deepening longing and transformation within the boundlessness of divine transcendence. Whereas Irenaeus conceives of deification as a process culminating in the incarnational work of Christ—wherein the divine image is restored and human destiny fulfilled—Gregory insists that this restoration is not the end, but the beginning of a deeper transformation. Because God’s nature is without limit, the soul’s participation in the divine cannot be brought to closure; rather, it continues into eternity as an unceasing ascent. Thus, while Irenaeus emphasizes the fulfillment of God’s salvific plan within history, Gregory expands that fulfillment into an eschatological horizon that remains forever open. For him, perfection is not a static state but a continual transformation in which the soul endlessly deepens its participation in God (Vita Moysis, II.239). While Irenaeus and Gregory of Nyssa articulate divergent emphases—one rooted in historical restoration, the other in mystical ascent—they are united by a shared conviction: theosis is not a sudden elevation or static transformation, but a dynamic process unfolding across time and eternity. For both thinkers, deification involves active participation in divine life, whether through Christ’s redemptive recapitulation of human nature or the soul’s ceaseless yearning toward the infinite God. Theological divergence here does not signal disagreement, but complementary insights into a mystery that is at once inaugurated in Christ and ever-deepening in its realization. Thus, theosis must be understood as a living movement—historically grounded yet never confined to history, perpetually inviting humanity into fuller communion with the divine.
2) How Irenaeus and Gregory together shape the doctrine of salvation
The correlation between Irenaeus’s and Gregory’s models of theosis has significant implications for contemporary theology, particularly in the areas of soteriology, biblical hermeneutics, and ecumenical dialogue. First, their shared emphasis on theosis as an ongoing process challenges static views of salvation that reduce it to a one-time event of justification. Both theologians present salvation as transformation, in which human beings are not merely declared righteous but progressively conformed to the divine nature. Irenaeus, by grounding theosis in the historical work of Christ, ensures that deification is not an abstract metaphysical concept but a tangible reality realized within salvation history. Gregory, by extending theosis beyond a historical framework, highlights that divine participation is never exhausted but always deepening. Together, these perspectives reinforce a participatory model of salvation, in which divine-human communion is not a passive reception but an active transformation that unfolds both in history and beyond.
Second, the synthesis of Irenaeus’s and Gregory’s theological models enriches biblical hermeneutics by integrating historical and mystical approaches to Scripture. Irenaeus’s typological exegesis demonstrates how salvation history finds its culmination in Christ, emphasizing the fulfillment of divine promises through the Incarnation. His reading of Adam-Christ parallels, particularly in Romans 5:12-21 and Ephesians 1:10, highlights the coherence of salvation history and the role of Christ in restoring humanity’s divine vocation. Gregory, by contrast, employs an allegorical and mystical exegesis, arguing that biblical figures such as Moses symbolize the soul’s continual ascent toward God. While Irenaeus’s hermeneutic ensures that theosis remains grounded in historical reality, Gregory’s approach opens up the inexhaustible depths of divine mystery, illustrating that participation in God is always expanding (Daniélou, 1944: p. 198). By integrating these approaches, modern theology can develop a richer biblical understanding of theosis—one that is both historically anchored and open to the infinite transcendence of God.
Finally, the dialogue between Irenaeus and Gregory carries important ecumenical implications, particularly in bridging Eastern and Western theological traditions. Theosis is often regarded as a distinctly Eastern Orthodox doctrine, yet Irenaeus’s Christocentric model demonstrates its deep resonance with Western theological frameworks. His emphasis on the Incarnation and the sacramental life of the Church aligns closely with Catholic and even Protestant theological concerns, particularly those that emphasize participation in Christ through the sacraments. Gregory’s mystical approach, meanwhile, resonates with contemplative traditions within Western Christianity, particularly in the writings of figures such as Augustine, Bernard of Clairvaux, and John of the Cross. By recognizing the complementary nature of Irenaeus’s and Gregory’s theological models, contemporary theology can foster greater dialogue between Eastern and Western traditions, offering a more integrated vision of theosis that unites historical, sacramental, and mystical dimensions of divine participation (Russell, 2004: p. 138).
3) Final Reflection: A Unified Model of Theosis
Engaging Irenaeus and Gregory of Nyssa in theological dialogue reveals that theosis cannot be reduced to a singular category—whether historical consummation or mystical progression—but must be grasped as a unity that spans both. In Irenaeus, the restoration of humanity’s divine vocation is decisively enacted in Christ’s Incarnation and mediated through the Church’s sacramental life. Yet Gregory compels us to see that this restored communion is not the terminus of the spiritual life, but its threshold: because God is inexhaustibly transcendent, the soul’s participation in divine life is likewise unending. Theosis thus unfolds in two interwoven movements—anchored historically in the redemptive acts of Christ, and ever-deepening as the soul journeys into divine infinitude. This synthesis offers not a compromise but a fuller vision of salvation: one that upholds the historical particularity of the Incarnation while refusing to enclose divine union within temporal limits. Far from presenting two incompatible systems, Irenaeus and Gregory each highlight essential dimensions of deification—historical and mystical, sacramental and eschatological, already accomplished in Christ and yet never complete. Their combined witness reframes theosis not as a static doctrine, but as the dynamic horizon of Christian existence itself.
In the end, the theological visions of Irenaeus and Gregory of Nyssa resist any flattening of salvation into either a juridical transaction or a mystical abstraction. Both insist that salvation is a transformative participation in the divine life—a process that begins with the historical Incarnation and continues through sacramental embodiment and spiritual ascent. Irenaeus grounds this reality in the concrete narrative of Christ’s redemptive work, while Gregory reveals its eschatological horizon as an eternal becoming. Together, they offer more than a synthesis; they invite a reframing of Christian existence itself—not as a completed state, but as a vocation to ever-deepening communion. This integrated vision of theosis, historically rooted and spiritually expansive, has the capacity to renew contemporary theological reflection across traditions, precisely because it holds in tension the temporal and the eternal, the sacramental and the mystical, the already and the not yet.
Ancient Sources
Gregory of Nyssa (1903). Oratio Catechetica (The Catechetical Oration). Cambridge University Press.
Gregory of Nyssa (1978). De Vita Moysis (The Life of Moses). In Classics of Western Spirituality (Translated by Abraham J. Malherbe and Everett Ferguson, Preface by John Meyendorff). Paulist Press.
Gregory of Nyssa (1993). In Ecclesiasten Homiliae (Homilies on Ecclesiastes). In S. G. Hall (Ed.), Proceedings of the 7th International Colloquium on Gregory of Nyssa. De Gruyter.
Gregory of Nyssa (2018). Contra Eunomium I. In M. Brugarolas (Ed.), Supplements to Vigiliae Christianae (Vol. 148, Translated by Stuart G. Hall). Brill.
Irenaeus of Lyons (1885). Adversus Haereses (against Heresies). In A. Roberts, J. Donaldson, & A. C. Coxe (Eds.), Ante-Nicene Fathers (Translated by Alexander Roberts and William Rambaut, Vol. 1, pp. 315-567). Christian Literature Publishing Co.
NOTES
1Irenaeus’s formulation here has become a cornerstone in patristic soteriology, later echoed by Athanasius in his famous phrase, “God became man so that man might become god” (De Incarnatione, 54). See also Behr, Irenaeus of Lyons, pp. 175-177, on the ontological implications of recapitulation.
2Irenaeus’s insistence on the Eucharist as both real and transformative stands in contrast to Gnostic denials of bodily salvation. See AH V.2.3 and Steenberg, Of God and Man, pp. 92-94, for a detailed treatment of Eucharistic realism in Irenaean theology.
3The term epéktasis is drawn from Philippians 3:13 (“stretching forward”) and became central to Gregory’s doctrine of eternal progress. For a full study, see Daniélou, Platonisme et théologie mystique, pp. 116-122.
4Gregory’s concept of divine plenitude reflects a departure from the Neoplatonic vision of static perfection. Instead, his theology valorizes motion as the structure of the soul’s perfection. On this dynamic metaphysics, see Ladner, The Idea of Reform, ch. 3.
5The attempt to hold together historical and mystical models of theosis reflects a broader challenge in modern theological anthropology. Behr and Russell offer different paradigms for doing so—Behr emphasizes the historical Incarnation, while Russell frames deification as a return to ontological unity with the divine.