Goings up, and advances and progress from glory to glory, the Light of the Trinity might shine upon the more illuminated. For this reason it was, I think, that He gradually came to dwell in the Disciples, measuring Himself out to them according to their capacity to receive Him, at the beginning of the Gospel, after the Passion, after the Ascension, making perfect their powers, being breathed upon them, and appearing in fiery tongues...You see lights breaking upon us, gradually; and the order of Theology, which it is better for us to keep, neither proclaiming things too suddenly, nor yet keeping them hidden to the end...He said that all things should be taught us by the Spirit when He should come to dwell amongst us. Of these things one, I take it, was the Deity of the Spirit Himself, made clear later on when such knowledge should be seasonable and capable of being received after our Saviour's restoration, when it would no longer be received with incredulity because of its marvellous character. For what greater thing than this did either He promise, or the Spirit teach. If indeed anything is to be considered great and worthy of the Majesty of God, which was either promised or taught...Look at these facts:--Christ is born; the Spirit is His Forerunner. He is baptized; the Spirit bears witness. He is tempted; the Spirit leads Him up. He works miracles; the Spirit accompanies them. He ascends; the Spirit takes His place.
-St. Gregory the Theologian, 5th Theological Oration