‘ … apocalyptic is a discursive idiom uniquely suited to articulate the radicality, sovereignty, and militancy of adventitious divine grace’ (p. xvii) and thus, argues Ziegler, apocalyptic is particularly relevant to, and especially necessary for, Protestant systematic theology. In Militant Grace, Ziegler brings together revised versions of thirteen essays published elsewhere between 2007 and 2017, into a sustained argument about the role of apocalyptic in Protestant theology. His argument, ‘that in pursuit of renewed accountability to the apocalyptic gospel, theology is required to think again about its own forms, methods, and foci precisely in virtue of its distinctively eschatological content’ (p. xv), is pursued in three sections.

In the first section, ‘The Shape and Sources of an Apocalyptic Theology’, Ziegler argues via the work of Gerhard Forde in favour of ‘the apocalyptic turn’ in theology over against interpretations of a historicising ‘cultural turn’ which rejects the apocalyptic. He then considers to what degree Karl Barth may be invoked by apocalyptic theologians, and closes the section by setting out six theses for ‘a Christian theology funded by a fresh hearing of New Testament apocalyptic’ (pp. 26–31).

The second section, ‘Christ, Spirit, and Salvation in an Apocalyptic Key’, exemplifies the theological programme advocated in the first section, making five forays into systematic theology through Pauline apocalyptic. These essays argue for the ‘royal office’ of Christ as a sovereignty of divine love, for a Christus Victor soteriology and for an eschatological pneumatology. Ziegler further considers the prayer ‘Thy kingdom come’ via Calvin and Barth, and the final judgment via Moltmann and Jüngle.

In the third section, ‘Living Faithfully at the Turn of the Ages’, Ziegler moves from systematic theology towards theological ethics, considering the implications of the proposed apocalyptic theology for Christian life. Ziegler analyses Protestant approaches to law in general and natural law in particular before considering Calvin on the moral subject of theological ethics, Kierkegaard on Christian self-understanding and apocalyptic in Bonhoeffer. The section and the book close with an argument for an apocalyptic understanding of Christian moral life as discipleship.

For any Protestant theologians who have not yet attended to the renewal of attention to apocalyptic in their discipline, this volume will serve well as a wide-ranging introduction to the questions, thinkers and possibilities at play in these discussions. And for those already familiar, the volume is an important distillation of the contributions of one of the leading voices in those discussions, particularly as they have taken shape in the ‘Explorations in Theology and Apocalyptic’ group which Ziegler leads in the AAR/SBL. The collection is an important and welcome contribution to the field.

Ziegler clearly specifies in the opening pages that the ‘Apocalyptic Turn’ referenced in the title is that which is focused primarily on Paul as apocalyptic, and the ‘Christian Theology’ referenced in the title is resolutely Protestant. It is, in one sense, unfair to criticise an author for only doing what he clearly states he has set out to do in the introduction of a book. However, I could not help but wonder about all that could be added to these conversations if they were truly about an apocalyptic turn in theology, beyond a turn in the interpretation of St Paul, and if they were truly about the future of Christian theology, beyond the Protestant horizons of Calvin, Barth, Bonhoeffer et al. Ziegler does make a significant gesture towards learning constructively from Anabaptist traditions in his closing essay on discipleship, which was a welcome and fruitful excursus; my critical question here is not merely about breadth of reading or ecumenical goodwill. My question is about the inherent limitations of an apocalyptic turn limited to Pauline texts and Protestant theologians, which inevitably leads the conversation to revolve around christology and soteriology to the neglect of broader implications of apocalyptic for the doctrine of God, the doctrine of creation in particular, and the theopolitical dimensions of these doctrines which arise from attention to the explicitly apocalyptic texts of scripture, as well as attention to pre-Reformation theologians, and the employment of apocalyptic in contemporary political theologies. Without attention to Hebrew apocalyptic there are also undertones of unintended supersessionism which seem to echo behind Pauline-focused emphases on the newness and rupture of the Christ event as central to understandings of apocalyptic in these conversations – which is not a criticism of Ziegler in particular, but a question for ongoing consideration in the discourse which he represents in this volume.