The goal of this book is to secure our knowledge of the triune God by rightly ordering the theological language with which we praise the triune God. Its central contention is that the manner of the Trinity’s revelation dictates the shape of the doctrine; it draws its dogmatic conclusions about how the doctrine should be handled on the basis of the way the Trinity was revealed. For this reason, The Triune God recommends some dogmatic principles for Trinitarian exegesis and offers systematic help for reconstructing the plausibility structures of biblical Trinitarianism. Since the book’s structure is intentionally unconventional, it is worth describing that structure in advance.
The first chapter begins with praise in order to invite a doxological attunement of the theological mind, issuing this summons: sursum corda! To contemplate the Trinity is to lift up your heart and to “set your mind on the things above.”1 No author can enforce such spiritual injunctions on a reader, but the history of writing treatises on the Trinity includes not only the tradition of invoking the Trinity, but of doing so in a way that enlists the reader’s strict and holy attention for what is essentially a spiritual exercise. Examples could be drawn from the early pages of nearly any theological work on the Trinity written from Irenaeus in the second century to John Owen in the seventeenth. But the prayer of Hilary of Poitiers at the conclusion of book 1 of On the Trinity is especially apt:
Therefore we wait for you to set in motion these timid first steps of our undertaking, to confirm it so that it may make progress, and to call us into fellowship with the Spirit who guided the prophets and apostles, so that we may apprehend their words in no other sense than that in which they spoke them, and explain the proper meanings of the words according to the realities they signify. For we shall be speaking of what they preached in mystery . . .
Grant us, therefore, precision of words, light of understanding, honorable speech, and true faith. Enable us to believe that which we also speak, so that we may confess you, one God our Father, and one Lord Jesus Christ as taught by the prophets and apostles; and now against the contradictions of the heretics, proclaim you as God (yet not solitary), and Him as God (not falsely).2
But the subjective tuning of the theologian’s intellect is not the only reason to begin with praise. Trinitarian theology, I argue, is essentially a doxological movement of thought that gives glory to the Father, Son, and Holy Spirit by beginning with confession of the work of God in salvation history and then reasoning back to its antecedent principles in God.
The second chapter sets the doctrine of the Trinity within a biblical theology of mystery, as that which “was kept secret for long ages but has now been disclosed” (Rom 16:25–26). The mode of revelation is crucial: God has made his triunity known through salvific actions joined inwardly to explanatory words. The “explanatory words” part of that formula has been unpopular in late modern theology, but it was as crucial to the original formulation of the doctrine as it is of abiding importance today. Without it, Trinitarian exegesis has become detached from divine revelation and has often floated free, vulnerable to prevailing winds of doctrine.
With verbal revelation restored as a constituent of Trinitarian revelation, chapter 3 considers the missions of the Son and Spirit as revelatory or communicative missions. These two sendings have made present among us a communication that overflows from the eternal conversation of the triune life. Taking seriously the fact that this revelation is the only source of our knowledge of the Trinity requires the demotion of experience and tradition to a lesser status. Each of them is considered as a possible foundation for the doctrine of the Trinity, and found wanting. Experience and tradition cannot even serve the more modest task of opening a means of access to the doctrine of the Trinity by themselves, because in both cases they are placeholders for appeals to revelation. Each, however, brings considerable benefits to Trinitarian theology when handled ministerially rather than magisterially—as servants, not masters. In what may be an unexpected move for a book that has already commended verbal inspiration and sola Scriptura, this chapter also takes care to set the biblical witness within a wider conceptual horizon, subordinating it to a more direct form of revelation.
That more direct form of revelation is the subject of chapter 4: Incarnation and Pentecost. Properly speaking, it is the visible missions of the Son and the Holy Spirit that constitute the actual revelation of God’s triunity. This chapter engages in an extended dogmatic description of the missions of the Son and the Holy Spirit, tracing the way these missions make known the eternal processions that are the life of the living God. These missions must be kept central in all our thinking about the Trinity. Failure to guard their biblical centrality with sufficient jealousy has been the root cause of much disorder and distraction in Trinitarian theology, cumbering the exegetical pathway and rendering Scripture opaque to Trinitarianism. Failure to recognize that they are manifestations of eternal processions has kept much modern Trinitarianism abstract and brittle. Recognizing the clarity and centrality of the triune missions is what makes the present study a constructive statement of Trinitarian theology that is shaped at every point by the mode of the revelation of the Trinity. The fundamental question posed in any theological interpretation of the missions of the Son and the Spirit is the question of what God has revealed about himself in them. The classic answer is eternal, internal processions.
Chapter 5 gives more direct attention to the divine processions, those internal actions of God that mark the divine life as triune. Based strictly on the incarnation and Pentecost, Trinitarian theology gives an account of the one God as three persons. This is the God of the gospel, the one who has made himself known when the Father sent the Son and the Holy Spirit. The exposition in this chapter also proceeds by addressing the most important theological terms that have proven useful for establishing good order in Trinitarian theology (processions, internal actions, persons), which relativizes the more recent habit of talking in terms of the economic Trinity and the immanent Trinity.
Chapter 6 connects these theological judgments to the task of exegesis. The church has always known that the doctrine of the Trinity is profoundly biblical and yet not straightforwardly taught in the Bible. The obliqueness of Trinitarianism’s exegetical foundation is both a blessing and a burden for Christian doctrine. In addition, the last few centuries have seen major changes in biblical interpretation, requiring that some traditional arguments be dropped, some new ones be acquired, and the entire approach to biblical Trinitarianism be put on a more secure footing.
Chapter 7 then turns to the attestation of the salvation-historical missions in their irreplaceably primary theological witness: the New Testament. The New Testament is indirect in its statements about the Trinity precisely because the actual revelation has already taken place in the personal advent of the Son and the Spirit, an extratextual event on which the New Testament documents are reflecting. I do not undertake a complete survey of New Testament Trinitarianism, but I do attend to the main lines of the Gospels and Epistles.
Only after attending to the coming of the Son and the Spirit, and then reading the New Testament reflections on them, do we turn to the Old Testament in chapter 8. Trinitarian interpretation of the Old Testament is an exercise in rereading, applying to the earlier part of a text what is learned from the later part. In the time period documented by the Old Testament, God was triune but was not actively revealing that triunity to his covenant people. Whatever adumbrations may be found in the text, no revelations are to be sought there, if we take both words literally: shadowing versus unveiling. For this reason, it is best not to press the Old Testament to make it yield Trinitarian revelation. The text of the Old Testament and the trajectory of its events do generate a host of unusual phenomena that need to be accounted for. They are best accounted for by Trinitarian theology as it throws a light backward from the New Testament to the Old. I commend the ancient practice of identifying divine speakers in the oracles of the old covenant (prosoponic exegesis), but consider and reject the tradition of identifying distinct Trinitarian presences in the Old Testament (christophanies).
The sequence of these chapters indicates the crucial order to be observed in our knowledge of the Trinity: revelation in the missions, attestation in the New Testament, adumbration in the Old Testament. Chapter 9 concludes the book with a series of summary theses on the revelation of the Trinity and its implications for a well-ordered doctrine of the Trinity and the overall shape of a theological system.
Readers may note that the history of doctrine receives little direct attention in this outline, especially relative to the amount of space devoted to hermeneutical concerns, biblical interpretation, and dogmatic description. Even if a more voluminous interaction with the history of doctrine might have strengthened the argument at many points, I hope its absence does not count as a weakness. At least I can offer the assurance that the mode of argument is intentional. By design, the biblical exposition and the doctrinal extrapolations drawn from it constitute the bulk of the volume and dictate its framework. The history of the doctrine of the Trinity is enchantingly rich, so much so that it can easily loom too large in a general treatment of Trinitarian theology, sometimes throwing off the balance. Too many books on the Trinity rush over the biblical discussion in a few pages (with sincere apologies) on the way to more extended discussions of historical development. If this book gives extensive discussion to scriptural issues and rushes by the history of doctrine (with sincere apologies), it does so in the hope of giving the impression that Trinitarianism is a gift of revelation before it is an achievement of the church. The alternative approach, while not illegitimate, risks giving the impression that the Bible delivers a relatively meager serving of raw materials that cannot be Trinitarian until they are cooked up into something hearty by theologians, who of course add a dash or two of their own spices. In spite of the absence of large-scale reporting on the history of doctrine, there is considerable interaction with major voices from the history of doctrine dispersed throughout the book, and I have frequently indicated where my arguments are indebted to and informed by the great tradition of Trinitarianism. A healthy deference to doctrinal tradition is indispensable to serious theology, and this book (appropriately for a volume in the New Studies in Dogmatics series) is an exercise in retrieval. But the way to retrieve the insights of the church fathers is not to pay more attention to them than to Scripture. It often seems that while patristic books about the Trinity were mostly about the Bible, even the best modern books about the Trinity are mostly about the church fathers. As long as it can be done without amnesia or ingratitude, the most patristic way to proceed is, after all, to study Scripture.
1. Colossians 3:2 NASB. The richness of the root phroneō in “τὰ ἄνω φρονεῖτε” accounts for the range of translations that have been offered for this exhortation, from “set your affections” to “think on.” John Davenant said that it “embraces two acts; the act of the mind or of the understanding reflecting about any thing; and the act of the will and affections approving and loving any thing” (An Exposition of the Epistle of St. Paul to the Colossians [London: Hamilton, Adams, 1832], 7). Is it plausible, and could it be exegetically responsible, to take the Trinity as the ultimate referent of τὰ ἄνω to which the apostle turns our minds? Only if the risen Christ’s sitting at the right hand of God (the proximate referent) and our inclusion in it (“your life is hidden”) can be construed, on the basis of the total witness of Scripture, as salvation-historical accomplishments that make known God’s eternal character as Father, Son, and Holy Spirit. The burden of this book is to show how this is so.
2. Hilary of Poitiers, On the Trinity 1:38, my translation.