In The Holy Trinity, Robert Letham quotes Gregory Nazianzen’s cogent statement on the Trinity’s progressive revelation within the history of the Bible:
The Old Testament proclaimed the Father openly, and the Son more obscurely. The New manifested the Son, and suggested the deity of the Spirit. Now the Spirit himself dwells among us, and supplies us with a clearer demonstration of himself. For it was not safe, when the Godhead of the Father was not yet acknowledged, plainly to proclaim the Son; nor when that of the Son was not yet received to burden us further…with the Holy Spirit…[I]t was necessary that, increasing little by little, and as David says, by ascensions from glory to glory, the full splendor of the Trinity should gradually shine (Robert Letham, The Holy Trinity, 33).
Gregory’s insights draw attention to the the wisdom of Christianity’s Triune God as he has gradually revealed himself as he really is and always (read: eternally) has been–God the Father, God the Son, and God the Holy Spirit. While all three existed in eternity together, only in the fullness of time is Triune Godhead seen in his manifold perfections. For those who read and teach the Bible, it must be kept in mind that God’s revelation is accomplished over time, and that the unchanging deity of the Bible is more clearly disclosed at the end of the story than at the beginning. While Gen. 1:1, 2, 3 arguably contain allusions to all three members of the Trinity, their disclosure is opaque, at best. This does not make Scripture contradictory or confused; it must be read in time (diachronically).
The progressive act of Trinitarian revelation shows God’s wisdom in teaching us, finite creations, who he is through escalating stages of revelation (cf. Heb. 1:1-3). Until we see how redemptive-history develops the Trinity over time, we will not be able to fully appreciate the oneness and the threeness of God–one Trinitarian being, three consubstantional persons; co-eternal in nature, fully revealed in their inter-penetrating distinctives in time.
There is so much here to fathom. May we continue to marvel at the uniqueness, the mystery, and the revelation of our living and true God.
Sola Deo Gloria, dss