No sooner do I conceive of the One than I am illumined by the Splendor of the Three; no sooner do I distinguish Them than I am carried back to the One. When I think of any One of the Three I think of Him as the Whole, and my eyes are filled, and the greater part of what I am thinking of escapes me. I cannot grasp the greatness of That One so as to attribute a greater greatness to the Rest. When I contemplate the Three together, I see but one torch, and cannot divide or measure out the Undivided Light.
– Gregory of Nazianzus, Oration 40, On Holy Baptism
Preached at Constantinople Jan. 6, 381