Gabrielle Thomas’ exploration of Gregory Nazianzen's doctrine of the image of God as preeminent marker of human identity adds itself to a sizable scholarship on the ‘image and likeness’ of God considered exegetically (Gen 1:26–27) and as a leitmotif in early Christian theological anthropology. Her work fills a gap, being the first major monograph focusing exclusively on Nazianzen's perspective on the imago Dei.

Thomas sets just the right tone, in my judgement, by outlining early on the dialectics of Gregory's theology of the image, which holds in tension the twin aspects of ‘divinity and vulnerability’, spirit and dust, and which takes strong cues from his Christology. For Gregory it is Jesus Christ, the New Adam, who grounds the dynamism and vocational dimension of the image, its being and becoming. Wisely, however, Thomas also draws attention to Gregory's unique view that the Holy Spirit was at work in the creation of the human image, avoiding a relegation of the Spirit's role purely to the experience of salvation.

Thomas revisits a number of early Christian speculations about the divine image prior to Gregory, including themes like the exact location of the image (soul or spirit only? soul and body?), the effect of the fall on obscuring the image and the precise ontology of God-likeness as a theme spanning biblical, Jewish and patristic literature. She notes how certain early Christian writers (e.g. Origen, Irenaeus) distinguished in Genesis 1 the endowed ‘image’ (εἰκών) and acquired ‘likeness’ (ὁμοίωσις), whereas Gregory tended to conflate the two. Surprisingly, Thomas does not mention, in this connection, the important perspective of Nazianzen's close associate Gregory of Nyssa, whose own conflation of image and likeness went far in demonstrating the strongly teleological orientation of this pair. Meanwhile, however, Thomas makes a strong case that the image of God is not just a grace granted to human nature but an identity to be fought for in struggle with the devil and the forces of evil. That identity has as its model Christ the Logos, the perfect image of God the Father and, as Gregory calls him, the ‘new mixture’ of God and humanity, whose kenotic descent makes possible our ascent in deification. Here Thomas is able to connect Nazianzen's doctrine of the image to the very core of his soteriology.

In a whole chapter on the cosmological background of the image of God in Gregory, Thomas brings back into view what, in her introduction, she noted as the vulnerability of the image. The human is, after all, mere ‘dust’ imprinted with divine likeness. The image signals both profound ontological fragility and an angelic dignity. Thomas interestingly draws upon Charles Taylor's notion of the ‘porous self’ in premodern western culture, the self more open to an external spiritual realm, a good analogy for the ‘permeability’ of the self to divine formation according to Gregory. This chapter is accented by Thomas’ analysis of Nazianzen's relatively unprecedented insistence on the fact that women are equally created in the image of the genderless God and enjoy all of its virtues.

Thomas’ final two chapters detail the ascetical and mystical dimensions of Gregory's teaching on the image. This includes a substantial investigation of Gregory's demonology and hamartiology, and his dialectics of the ‘flesh’ as a seat of vulnerability but also a matrix of ascetical virtue. Engaging with a voluminous scholarship on deification in Nazianzen and the broader Greek patristic tradition, Thomas provides a splendid and nuanced treatment of the various ascetical, ethical, sacramental (especially baptismal) and eschatological aspects of theosis. Deification for Gregory brings to full fruition the endowed divinity of the image, which, in its sanctity, commands the devil's worship.

I find scarce shortcomings in Thomas’ monograph. There are a few places where her argument could have been strengthened by more direct comparison with the insights of the other two Cappadocians, especially Gregory of Nyssa, who factors very little in the book. One such motif that certainly warrants comparison is precisely one of Thomas’ master-themes, the dynamism and so too the tension between power and vulnerability in the human image of God. Nyssen's own vision of the moral and spiritual growth of the Christian includes a strong emphasis on the positive flux of life, the relentless change from instability to stability, from vicious passions to virtuous ones, from chaos to new creation. That aside, Thomas’ book is to be credited for its copious attention to biblical frames of reference, and to the full range of Nazianzen's writings, including the poetry, in the development of his theological anthropology and doctrine of the image of God. Her study will doubtless hold great benefit for those exploring other aspects of Gregory's thought, including his Christology and eschatology.