Narrowly speaking, the Bible does not provide us with an exhaustive (or even fully explicit) theology of the Trinity. The Bible does teach the doctrine of the Trinity, to be sure, but it does so by implication. It gives us the revelation of Father, Son, and Holy Spirit, and it tells us that these three are one, in various ways. Anyone who has studied the history of the theological explanation of the Trinity, however, knows that this is only the starting gate of the discussion. At no point did Arians, Sabellians, Eunomians, or any of the various Homoian groups flatly reject scriptural verses. The debate was always over interpretation and implication. This is not illegitimate, nor is its admission any departure from traditional Protestant Christianity. Calvinists have always insisted on the need to deduce “good and necessary consequences” from the Bible and to insist that those too are part of the whole counsel of God (WCF 1.6).
This little preamble is necessary because of the recent shift to speaking of “Trinitarianism” or explicitly “Trinitarian” formulations of dogmatics. This manner of speech capitalizes on the historic importance placed upon the doctrine of the Trinity and the rightful recognition that the doctrine of the Trinity is one of the unique confessions of Christianity. What is less frequently admitted is that to appeal to “the Trinity” is to appeal to a specific theological construct and an objective tradition of theologizing. There really is a specific referent when we say “the Trinity,” and it includes a number of basic doctrines. Unfortunately many of these basic doctrines are either unknown or rejected by a good many of modern theologians who wish to cash in on the value of the term “Trinity.” Therefore it will be necessary to lay out explicitly a number of the basic doctrines which underlay the theology of “the Trinity” in order for us all to be speaking of the same thing. It will be the goal of this series to make plain what “the Trinity” actually means in historic Christian dogma.
We must also say that while the doctrine of the Trinity is supra-rational, it is not irrational. At no point do Christians concede that the formulation of the Trinity is a violation of logic. It is a mystery, to be sure, but not a contradiction. Therefore it is appropriate to use reason in the service of dogmatics, and it will not be deemed wrong to ask for clarity and consistency in our discussions. Such is the classic Reformed position.
