“This I give you to share, and to defend all your life, the One Godhead and Power, found in the Three in Unity, and comprising the Three separately; not unequal, in substances or natures, neither increased nor diminished by superiorities or inferiorities; in every respect equal, in every respect the same; just as the beauty and the greatness of the heavens is one; the infinite conjunction of Three Infinite Ones, Each God when considered in Himself; as the Father so the Son; as the Son so the Holy Spirit; the Three One God when contemplated together; Each God because Consubstantial; One God because of the Monarchia. No sooner do I conceive of the One than I am illumined by the Splendour 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, Orations 40.41 (preached at Constantinople Jan. 6, 381)