Trinitarian Theology and Reformed Catholicity

Michael Allen and Scott Swain’s book Reformed Catholicity: The Promise of Retrieval for Theology and Biblical Interpretation was published in 2015, announcing a theological program that was in some way ahead of its time. So it’s appropriate for the journal Reformed Faith and Practice to mark the book’s ten-year anniversary by soliciting a set of brief reflections on the book, its reception, and the current state of play for a project like reformed catholicity. I was invited to reflect on “Trinitarian Theology and Reformed Catholicity” in that Spring 2025 issue (vol 9, issue 2). The whole issue is free, online, and full of interesting analysis; click through for it.

Here’s my 1000-word piece:

With its programmatic outlook, its cross-disciplinary venturesomeness, and its broad, journalistic reportage of (then-) current trends in theology and church life, Allen and Swain’s little book Reformed Catholicity (2015) has a lot going on. Without denying the book’s explanatory helpfulness as a guide to the times, or its power as a manifesto for a movement of sorts, I want to direct attention to the fact that Reformed Catholicity is in fact mostly a book about Scripture. It is first and foremost an entry in the bibliography of bibliology, a book about the Bible.

This is worth emphasizing ten years on because both then and now, the theological reading public is easily distractable. Nearly anything will turn our heads. The notion of retrieval, though safely buried in the book’s subtitle, can easily draw disproportionate attention. It raises truly fascinating questions about history and contemporaneity, about cultural powers of transmission and reception, about tradition and traditions (in Yves Congar’s formula). Meanwhile up in the main title, the frisson of adding the adjective “Reformed” to the noun “Catholicity” is intentionally arresting. The juxtaposition invites us to align with Team Reformed and/or Team Catholic, to declare whether one or both ought to be uppercased or lowercased, and to work out a theology of ecumenical positioning. All of this, along with other matters of “theological culture” are really present in the book, and in their own way worth pondering. Allen and Swain in fact deliver an incisive set of observations on 2015’s theological culture, and (especially) excellent guidelines for how to encourage a more faithful theological culture in church and academy.

But none of this retrievalish-ecumenical-cultural material has any solid basis or staying power except insofar as it is related to the Bible as the word of God. What is it that we are retrieving, receiving, transmitting, explaining, and forming interpretive cultures around? Scripture. The answer is characteristically Protestant, and Reformed Catholicity delivers it fittingly, in the form of a doctrine of Scripture. Two of its chapters retrieve (yes) the traditional Protestant doctrine of sola scriptura with greater amplitude than conventional wisdom expects; the final chapter defends (the right kind of) proof texting as an effective, and inherently apostolic, technique for signaling the vital relationship between biblical interpretation and doctrinal judgements. It is in service to this biblical core that Allen and Swain deploy all the other elements of Reformed Catholicity–both the book and the ongoing project.

In other words, the ongoing project of Reformed Catholicity is an outworking of what John Webster (to whom the book is dedicated) called “the domain of the word” of God. Will Protestant theology take seriously the charge to receive Scripture responsibly, and behave as befits a church to whom this word has come? Will it equip itself with an appropriate understanding of the church as the creature of the word, of its public teaching as a confession of the fullness of the faith, and of the long tradition of biblical interpretation as an extended engagement with the biblical text itself? These remain live questions. How has this project (“a theological sensibility, not a system”) fared since the manifesto’s publication? There are reasons to be encouraged, especially from the point of view of systematic theology and specifically trinitarian theology.

The year 2016 was something of a stress test for evangelical commitment to the traditional lines of the doctrine of God, as a wide-ranging controversy broke out over a dense cluster of issues in trinitarian theology. Different publics no doubt learned different lessons from the struggle. But to hazard a generalization, many students were awakened from their slumbers by the very fact that a disagreement existed. Neglected facets of trinitarianism (eternal generation, inseparable operations, appropriations) gained prominence, as teachers poured out first blogs and then books to provide a deeply catechetical re-introduction of the doctrine of God along traditional, Nicene lines. In the edited volume Retrieving Eternal Generation (Zondervan Academic, 2017), numerous authors canvassed the biblical, historical, and doctrinal case for this cornerstone doctrine. Adonis Vidu published an unprecedented monograph on inseparable operations (The Same God who Works All Things: Inseparable Operations in Trinitarian Theology (Eerdmans, 2021)). Finally, the large volume edited by Matthew Barrett, On Classical Trinitarianism: Retrieving the Nicene Doctrine of the Triune God (IVP Academic, 2024) manages to be simultaneously the broadest coalition of writers and topics, and also the most focused on settling the original controversy, especially refuting overly social trinitarianism and any eternal functional subordination of the Son.

About five years after the outbreak of that controversy, 2022 brought a kind of annus mirabilis for evangelical trinitarianism, with a trio of remarkable books: R. B. Jamieson and Tyler R. Wittman’s Biblical Reasoning: Christological and Trinitarian Rules for Exegesis (Baker Academic, 2022); Steven Duby’s Jesus and the God of Classical Theism: Biblical Christology in Light of the Doctrine of God (Baker Academic, 2022); and Glenn Butner’s Trinitarian Dogmatics: Exploring the Grammar of the Christian Doctrine of God (Baker Academic, 2022). It is hard to imagine a set of books that could more powerfully carry out the aspirations of Reformed Catholicity in the doctrine of God than these. They all three display exegetical care (but especially Jamieson and Wittman, a New Testament/systematics team), philosophical seriousness (but especially Duby, with enviable scholastic chops), and ecumenical sensibility (but especially Butner, with an impressive command of the literature).

What are the future prospects of Reformed Catholicity in this area? Does this theological sensibility have the power to articulate a well-developed doctrine of God that is both reformed and catholic? Again, there are auspicious signs. The next steps will be in developing even stronger habits of reading the Bible with the theological depth it calls for. Kevin Vanhoozer’s comprehensive Mere Christian Hermeneutics: Transfiguring What It Means to Read the Bible Theologically (Zondervan Academic, 2024) is a kind of master synthesis of the hermeneutical program, while a number of commentators are emerging who are both competent and confident to carry out theological interpretation at a high level: consider Michael Morales’ two volumes on Numbers (Apollos Old Testament Commentary series, 2024) and Steven Duby’s Habakkuk (T&T Clark International Theological Commentary series, 2025). As this movement of Bible interpretation matures and draws more practitioners, the time will be ripe for a fuller articulation of trinitarian theology that better catches the cadences and tones of the Bible’s own way of speaking. Such a consummation, devoutly to be wished, will be a fitting result of a principled and large-minded championing of the Protestant doctrine of Scripture as the source of true and enduring catholicity.