The simplicity and assurance with which the New Testament writers speak of God as a Trinity have, however, a further implication. If they betray no sense of novelty in so speaking of Him, this is undoubtedly in part because it was no longer a novelty so to speak of Him. It is clear, in other words, that, as we read the New Testament, we are not witnessing the birth of a new conception of God. . . . The whole book is Trinitarian to the core; all its teaching is built on the assumption of the Trinity; and its allusions to the Trinity are frequent, cursory, easy and confident.
The doctrine of the Trinity . . . takes its place in its pages . . . with an air almost of complaint, already “in full completeness,” leaving no trace of its growth. “There is nothing more wonderful in the history of human thought,” says Sanday, “than the silent and imperceptible way in which this doctrine, to us so difficult, took its place without struggle – and without controversy – among accepted Christian truths.”
Our New Testament is not a record of the development of the doctrine or of its assimilation. It everywhere presupposes the doctrine as the fixed possession of the Christian community; and the process by which it became the possession of the Christian community lies behind the New Testament.