Ever wonder why there’s not a verse in the Bible, like, right up front in Genesis or something, that says: “God is a Trinity, three in One,” or something like that? Why didn’t He just come out and say it?
Here’s a take on this question from Gregory Nazianzen, the 4th century Christian leader:
“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 forth.”
So maybe it was our fallenness, our issues, that prompted God to reveal Himself slowly, over time? It’s an interesting thought…
(Quote taken from The Holy Trinity by Robert Letham)