While the locus classicus appears at 2 Pet 1:4 and our sharing in the divine nature, it was Irenaeus of Lyon (d. c. 200) who first developed an extensive theology of Christian deification. In his skirmishes with the gnostic Valentinians and their fundamental belief that human persons possessed a ‘natural divinity’, Irenaeus instead pointed to the divinizing godliness available only in the enfleshed Christ and in his Eucharist which extends the deifying effects of the Incarnation throughout all time.Footnote ¹ From the end of the second century onwards, then, the best of Christian theology tended to explain human salvation as theopoiesis(a term first christianized by Clement of AlexandriaFootnote ²), as becoming a god. Far from the legalism indicative of some later soteriologies, the early church saw discipleship not so much as a matter of fulfilling various ethical prescriptions but more as the faithful's taking on properly divine attributes: a blissful immortality, a fiery love, an unquenchable joy. It happens whenever two persons in love spend time together: they slowly become like the other—perhaps even becoming in some ways indistinguishable. Or, as St. Paul came to realize, ‘no longer I, but Christ lives in me’(Gal 2:20). In Christ, God became like us; in our lives of service and sacramental worship, we are thus invited to become like God.

A noticeable return to this central theme of the Christian life marks much theological activity in the past few years. For example, the third edition of the Oxford Dictionary of the Christian Church finally decided to record an entry on deification,Footnote ³ and Jules Gross’ 1938 masterpiece, La divinization du Chrétien d’après les pères grecs: Contribution historique à la doctrine de la grâce has become available in English.Footnote ⁴ Comparative studies have likewise proven fruitful in showing how the East and the West have much more in common here than usually thought, dissuading us from the prevailing stereotype that Greek thought is exclusive in elevating and transforming the human person into a gloriously divine creature while the Latins concentrated simply on the sacrifice of Calvary and its subsequent juridical atonement. A.N. Williams has juxtaposed the theological representative of the West, St. Thomas Aquinas, with his oriental counterpart, Gregory Palamas (d. 1359),Footnote ⁵ whereas, in a more evangelisch tone, Reinard Floghaus uses Palamas alongside Martin Luther in order to bring out various patterns of deification in Reformation thought.Footnote ⁶ In Spain Pedro López has produced an excellent overview,Footnote ⁷ while a recently published German dissertation calls for a shift in catechetical training toward the stark proclamation that the goal of all Christian education is to ‘become gods’.Footnote ⁸

Even the new Catechism of the Catholic Church has made official what had always been taught. Relying on the ancient voices of Irenaeus, Athanasius, and Aquinas, respectively, we read: ‘“this is why the Word became man, and the Son of God became the Son of man: so that man, by entering into communion with the Word and thus receiving divine sonship, might become a son of God.”“For the Son of God became man so that we might become God.”“The only-begotten Son of God, wanting to make us sharers in his divinity, assumed our nature, so that he, made man, might make men gods.”’Footnote ⁹ If both academy and ecclesia are reawakening to the richness of the doctrine of deification, a survey of its recent literature is well in order. This essay accordingly reviews the most recent English studies in this area, uncovering three main types of works: the broad survey, the more concentrated focus, and the wider theological project reliant upon the classical elements of deification.

The first type of work is the major sweep through the history of deification. The most comprehensive text here is clearly Norman Russell's The The Doctrine of Deification in the Greek Patristic Tradition.Footnote ¹⁰ Russell begins with a very illuminating walk through the origins and development of the various approaches to deification in the early church; he is the only one to spend any amount of time on divinization in the Graeco-Roman (ch. 2) and Jewish worlds (ch. 3), indispensable contrapositions in understanding the uniqueness of Christian deification. Chapter 4 examines the earliest forms of Christian thought: Pauline, Johannine, as well as the 2^nd century apologists, up through Irenaeus and Hippolytus of Rome. Chapters 5 and 6 treat the city of Alexandria, nimbly divided between deification as understood in the multiple schools there, and then from the side of episcopal control. The next chapters deal with the Cappadocian contributions (ch. 7) and then on to monasticism as a collective term (ch. 8), concentrating especially on Maximus the Confessor, Evagrius Ponticus, Diadochus and Dionysius the Areopagite. Russell concludes not only with an epilogue on later authors—Leonitus (d. c. late 6^th century), John Damascene (d. 750), Symeon the New Theologian (d. 1022), and Palamas, but with appendices examining the Syrian and Western forms of deification as well.

This magisterial study will no doubt replace Gross’ classic for a new generation for at least three reasons. The greatest contribution of Russell is the splendid attention with which he works through how standard deifying taxonomy changes and has adapted to related theological trends throughout the millennia. After all, the Pauline images of adoption and co-heredity with Christ and the earliest Christian explanations of humanity's participatory union in the divine are consistent with yet quite inchoate when compared with later concepts such as the sacraments as deifying agents as found in Maximus or the total spiritualization of the human person as found in Symeon. Not only are such developments highlighted but so are the images which had to be suppressed: for example, the Nestorian controversy put an end to the Christian usage of apotheosis to describe the sanctified humanity of the Logos; and ektheosis, a term any churchman could have employed to describe the rational creature's participation in divinity, was in fact an instrumental term within the theurgic rites of later Neoplatonism and therefore never found a home among Christian theologians. Secondly, Russell is singular in his attention to non-Christian influences when it comes to how this development took place. He is able to show connections with very obscure but nonetheless important sources: from early Hebrew angelology and Hekhalot mysticism (the spiritual literature of the Talmudic period) to the Hermetica and Pythagoreanism of later antiquity. Appendix 2 (pp. 333–44) is likewise entirely devoted to ‘The Greek Vocabulary of Deification’ and shows how pivotal Greek terms were developed and employed. Thirdly, unlike most, Russell realizes that there is a distinct approach to deification in the West and accordingly offers brief treatments of Tertullian, Hilary of Poitiers, and of St. Augustine (pp. 325–32).

A more abridged version of this type of overview is George Maloney's finely titled, The Undreamed Has Happened: God Lives Within Us.Footnote ¹¹ Maloney's text follows the standard pattern in such works: beginning with Irenaeus and tracing the development of deification up through Palamas. Chapters 1–6 concentrate mainly on the interplay between anthropology and Christology in the early church: Adam foreshadows the incarnate Christ, whose descent into human flesh not only restores what was freely forfeited in Eden but elevates and transforms humanity into something incorruptible and immortal, in short, godly. The passages treated here come from the New Testament, the second century Apologists, Irenaeus, Origen, and the Cappadocians. Each of the next five chapters (7–11) is dedicated to a theologian who developed a very detailed theology of deification: Cyril of Alexandria, Dionysius the Areopagite, Maximus the Confessor, John Damascene, and Palamas.

Since this book intends to serve as an accessible introduction into a difficult theme, Maloney chooses not to stray into technical philosophical or theological subtleties. That said, however, his treatment of human participation in divinity as well as the distinction between essence and energies in God prove illuminating. On this latter point, he does a nice job in showing why a majority of Eastern theologians differentiate between God's immanent nature (essence) and the relationships within God (energies), allowing creatures to be drawn into the mystery of the Trinity. Given the metaphysical framework of the Greek tradition, this is a necessary distinction, which at once both upholds God's otherness and nonetheless allows men and women to share in the divine life. Among all of these studies under review, Mahoney offers us a unique glimpse (pp. 179–208) at the ascendancy of deifying themes in twentieth-century theologians not normally associated with divinization: Karl Barth, Paul Tillich and Karl Rahner.

The next type of work is the more specialized monograph, treating one particular figure or question. The earlier of these works comes from Donald Fairbairn and his thesis that the main thinkers of the fifth century reveal two competing understandings of the Incarnation alongside two corresponding understandings of grace.Footnote ¹² To show this connection he pits Theodore of Mopsuestia and Nestorius against Cyril of Alexandria and John Cassian (the latter chosen because of his working relationship with Pope Leo, eliminating Augustine due to the Bishop of Hippo's lack of involvement at Chalcedon as well as his distance from the East's Christological debates). The issue at stake is really whether or not the fullness of God entered human history in an efficacious manner and, if so, how.

On the one hand, Theodore and Nestorius understood Jesus to be the supreme instance and mediator of the divine life. In such a Christology, however, how grace is imparted becomes problematic. Why so? Technically, here grace is neither connatural nor identifiable with the man Jesus; if he is in a special position to transmit grace, it is only because he is its uniquely perfect recipient. As Fairbairn rightly assesses this position, the difference between the divine life in Jesus and in his followers is one of mere degree. Yet, if grace comes from human agency only, it proves to be humanly restorative, but never divinely transformative. Such a divisive Christology must see salvation as again establishing Eden but it can never promise Paradise. Having fallen from Adam and Eve, we may again become like them, but we will never become like the divine: ‘It is the assumed man's incorruption and immortality that Christians will receive in the future, not the incorruption of God the Logos himself’(p. 60). This is problematic because if the mediator's two natures are ontologically bifurcated, he can never bring humanity into contact with divinity but with only a more refined, purer sense of the human. Salvation is thus understood not as sharing God's own life but as returning to what our first parents enjoyed before they freely turned away from God.

Cyril and Cassian, on the other hand, can stress salvation as deification because the incarnate Logos is truly active in the concretely human. Following Athanasius’ economic rationale for Jesus’ full divinity—we can be divinized only if Jesus is fully divine—Cyril and Cassian are able to maintain a theology of deification because the fullness of God is present and active in the humanity of Jesus. Furthermore, if Jesus is said to have become incarnate so as to give himself to human persons, ‘then to say that he gives us himself in grace can hardly mean only that he gives us some “physical” and moral qualities that he possesses. Instead, one would expect a person to give us something personal, and sonship [sic] is a crucial part of Cyril's idea of salvation’(pp. 76–77). Unlike a restorative soteriology, this understanding of grace and of Christ actually transforms human persons and elevates them into sons and daughters of God. While this theme is stronger in Cyril than in Cassian, Fairbairn nicely shows how Cassian similarly holds a theory of deification in analogous fashion (pp. 162–65). As a monk more detached from the episcopal duties facing Cyril, Cassian was able to develop a sense of divine communion emphasizing both individual asceticism and communal life, not as ungraced attempts to reach God (as the usual Pelagian reading of Cassian tells the story) but as ways of recognizing and cooperating with the divine's ongoing penetration into the human agent. Therefore, since Jesus was recognized by Cassian and Cyril as being no less consubstantial with his divine Father as he was with his human mother, he could effect humanity's participation in the divine nature in such a way that Nestorius and Theodore's Jesus, the perfect recipient of grace, could not. These juxtapositions and the implications Fairbairn draws out of them are excellent contributions to understanding the history of deification.

The second work in this more focused genre looking at the divinizing work of Christ appears in Daniel Keating's The Appropriation of Divine Life in Cyril of Alexandria.Footnote ¹³ Keating explains why he chooses ‘appropriation’ over other terms, because it best represents ‘the action of both parties in the transaction of divine life…appropriated to us by Christ, and appropriated by us in Christ’(p. 9). Within all these works reviewed here, Cyril has received more attention than any other theologian, and what Fairbairn prepared us to see, Keating goes in depth to make explicit, drawing out important topics left otherwise untouched.

Keating divides his work into 6 chapters. The first treats the ‘divine plan of salvation’ in Cyril, a narrative in which the life of Christ teaches humanity the significance of participation in God's life. Relying primarily on Cyril's Gospel commentaries (especially on Pusey's translation of his Commentary on John), biblical scenes are stitched together to trace how Adam lost the intended life offered to all of humanity but how the Second Adam now makes available an even more intimate union with the Trinity. Ch. 2 accordingly examines how Cyril presents the sacraments as the means by which the children of Adam are sanctified, receiving new life in baptism and continually renewed in the Eucharist. Such an in-depth study of the sacraments was absent in Fairbairn's study but proves essential in understanding the Cyrillian approach: ‘Cyril likens our participation in the Eucharist to “wax joined to wax”, as we become intermingled with Christ through the mingling of his flesh with ours’(p. 69). Given such a realist understanding of the sacraments, Cyril has no problem showing how the Word made flesh enters the human person and how the Holy Spirit comes to live in men and women.

Keating therefore spends the next two chapters on Cyril's understanding of indwelling and the effects that participating in the divine nature should manifest in the Christian's new life. In order to do this, Keating must treat the multi-faceted way Cyril explains human-divine communion. Always referring his audience back to Christ's sanctified humanity as both pattern and agent of our divinization, Cyril comes to develop an elaborate sense of external relationship so as not to seem to absorb the human into the divine; but he also comes to infuse new meanings into the Platonic understanding of the contingent's participation in the absolute and eternal, especially as he elucidates (albeit minimally) II Pet 1:4. Similar to Russell above, Keating uses the final chapter to compare Cyril's understanding of deification with Theodore of Mopsuestia, Augustine of Hippo, and Leo the Great. Regarding the first, he reaches more or less the same conclusions as Fairbairn; regarding Augustine and Leo, Keating carefully shows how theosis should be understood as a central component of standard Latin theologies.

Most recently, Adam Cooper has taken up the deification of Maximus the Confessor (d. 662), an essential figure when discussing the history of deification. The Body in St. Maximus the Confessor: Holy Flesh, Wholly Deified Footnote ¹⁴ is particularly important because, first, it is a full-length work in English to treat Maximus’ characteristic—because so comprehensive—concept of deification (exemplary studies exist in German by von Balthasar and Schönborn) and, second, it offers us an illuminating concentration on what Christ's theandric presence actually does to corporality by imbuing it with the Spirit. The paradigm with which to inquire into this new state proves to be the transfiguration of Jesus himself, whose human flesh unveiled the glory of the Father. To explore such a shining forth, Cooper cleverly devises his chapters into corporeality and concealment (ch. 1), corporality and cosmos (ch. 2), corporality and Christ (ch. 3), corporality and the Church (ch. 4), and corporeality and the Christian (ch. 5). By grounding his study in creation, Cooper develops an indispensable arc from protology to soteriology, and we begin by understanding the material as that which has been divinely designed so as to reveal the inner workings of God ad extra.

The deiformity inherent throughout creation expresses the divine desire to become embodied in history. According to Cooper, here ‘lies the possibility of fallen creation's return to and fulfilment of its true destiny. And in the incarnation, established in history in the person and work of Jesus Christ and worked out in the lives of the baptized, that possibility has become an empirical fact. Deified creation already exists, ‘wholly deified’, as the body of Christ’(p. 251). In this way, Maximus invites his auditors to understand how the cosmos acts as a prelude to the deification of matter, epitomized and effected in Jesus’ transfigured humanity. For it is the Incarnation to which all embodiment points and from which all divinization flows, causing a new humanity which remains wholly corporeal, yet is now interpenetrated with the Spirit and hence lifted above any disintegration or corrosion.

The third genre of work is the doctrinal or scriptural work, which distinguishes itself by recovering deification as the capstone that structures and guides its theological speculation. In Divine Becoming: Rethinking Jesus and Incarnation, Charlene Burns attempts to show how the whole of Christian thought is ultimately about extending the divine humanity of Christ to all human persons.Footnote ¹⁵ Professor of theology at the University of Wisconsin-Eau Claire, Burns sets out to recast the Incarnation in terms of participation and the interrelatedness of God's creation. The ultimate purpose of this work is to make a case for a Christology of participation in which the man Jesus ‘incarnates not the divine nature, as in the sense of ousia or being, but incarnates God in his “radical devotion to God.” In and through the presence of grace in Jesus, God is constitutive of who Jesus is’(p. 117). Accordingly, Burns calibrates this Christology with her understanding of deification, or ‘divine becoming’, forbidding us to think of the Christ-event as a uniquely unrepeatable occurrence and more of a paradigm how each human person can be before God. She begins by providing a sketch of the history of Christology (ch. 1–3), and then draws mainly from Karl Rahner in order to develop an empathetic, relational view of God (ch. 4), a relational anthropology (ch. 5), a participatory Christology (ch. 6), and then turns to Buddhism so as to reformulate how Christians can think of both evil and community (ch. 7).

While there are some wonderful insights in these chapters, this is not an unproblematic text, exhibiting precisely the dualistic Christology Fairbairn above critiques. That is, in her denial that the Incarnation ‘an ontologically unique event’(p. 7) or ‘that God's presence to Jesus is qualitatively different than God's presence to the rest of humanity’(p. 134), Burns pushes the (later) Rahnerian understanding of Christ as the ‘highest instance’ of humanity in a pernicious fashion. All too often she speaks of how ‘Jesus became the Christ in that he found his true reality in the very being of God’(p. 144), or of a Jesus who must accept ‘the presence of the divine made incarnate in him’(p. 158), and hence implying a human suppositum who at some point in time comes to participate in divinity. Therefore, by purposefully dismissing the Chalcedonian structure of a divine person's substantially uniting himself to a created nature, Burns wants to make Jesus of Nazareth the ‘symbolic means through which God has been revealed as the matrix of relationality’(p. 127). However, if what Jesus offers us is ‘participation in the divine’ and not divinity itself, if he is God's ‘offer fully accepted’ and not the offer itself (p. 134), Burns finds herself unwittingly mired with the Nestorians and Theodores of old and the Haights of today (in fact, what Burns advances here echoes exactly Eusebius of Nicomedia's contention that the Son participates in the Father, firmly rejected by AthanasiusFootnote ¹⁶). Ironically, Burns’ Christ cannot deify because he is not substantially identifiable with divinity and thus it is never his to give—nemo dat quod non habet. Perhaps, then, it is no wonder why she chooses to conclude her text with a chapter on the merits of deification as proffered by Buddhism.

Michael Casey is a Cistercian at Tarrawarra Abbey in Australia and his latest takes the reader through the Gospel of Mark in order to uncover how Christ is portrayed as the one who became human in order to make humans like himself. In Fully Human-Fully Divine: An Interactive Christology,Footnote ¹⁷ Casey shows how Mark wants his reader to understand how the Son's incarnation and each of Jesus’ actions aim at actuating human godliness. This is what he means by an ‘interactive Christology’, that there is an exchange of properties between the human and divine: ‘The Incarnation makes no sense without the corresponding doctrine of our divinization. God's Son descended so that we might ascend, that we might share the divinity of him who humbled himself to share our humanity…Our vocation is to be receivers of the fullness of the Word made flesh’(p. 8). Casey proceeds in this way, prayerfully taking up 25 various themes, such as quietness, ambiguity, nakedness, and eternity, and works orderly through Mark's life of Jesus so as to show how each page invites us to let Christ form our lives and our relationships in his Spirit. This text proves to be tremendously insightful and helpful, especially for anyone working through the Gospel of Mark.

Also included in this third category is the most recent work out of a group of Christian scholars from Finland trying to establish a distinct theological voice. Mainly due to their geographical proximity to Russia and the Orthodox way of theologizing, Finnish thinkers have spent the past decade or so reclaiming divinizing trends in how they approach the Christian tradition. Among the forerunners here are Tuomo Mannermaa and Veli-Matti Kärkkäinen. Mannermaa is probably best known for his work on showing how a very significant pattern of divinization runs through the thought of Martin LutherFootnote ¹⁸ and Kärkkäinen is very indebted to his insights. Kärkkäinen is professor of theology at Fuller Seminary in Pasadena as well as of ecumenical theology at the University of Helsinki and his One With God: Salvation as Deification and Justification is an illuminating treatment of both the history of deification as well as newer trends today.Footnote ¹⁹ Given his unique perspective, Kärkkäinen is able both to draw from thinkers not yet explored, such as Nicholas Cabasilas (d. 1322), and pay attention to the more forgotten schools of thought, as the Lutheran, Anabaptist, Methodist, and Pentecostal views of deification are all briefly treated here.

After an introduction and a survey of recent New Testament scholarship, Kärkkäinen's third chapter relies mainly on Vladimir Lossky's works to outline theosis in the Orthodox traditions and thus provide a groundwork for the rest of his study. Ch. 4 treats divinizing elements in Martin Luther's thought, especially where it has been neglected, such as in his theology of the cross as well as in his understanding of justification. The later Protestant traditions which Luther occasioned are treated in ch. 5. The final two chapters then propose an ‘ecumenical convergence’ regarding soteriology (ch. 6) and the role of the Holy Spirit in effecting divine union (ch. 7). Overall, these chapters are some of the more accessible of all the studies reviewed here and Kärkkäinen is to be commended for brining so many otherwise neglected perspectives to our attention.

If intimacy with God is the consummation of all Christianity promises, we must be continually reawakened to the richness of what a soteriology of deification offers. These texts which take up the beauty and intricacies of humanity's divinization are correspondingly fitting and much welcomed. For they not only provide scholarly treatments of an ancient Christian theme, they also serve as a call for further study in reinterpreting the church's message as one of becoming Christ, of becoming fully human in godliness.