Hortatory Address to the Greeks

And Pythagoras, son of Mnesarchus, who explained his philosophical teachings through symbols, as those who have written his life show, seems to have held thoughts about the unity of God that reflect his time in Egypt. When he says that unity is the first principle of everything and the cause of all good, he indicates through an allegory that God is one and alone. This is evident from his claim that unity and one are quite different. He states that unity belongs to the category of things understood by the mind, while one belongs to numbers. If you want clearer evidence of Pythagoras's view on one God, consider his own words: “God is one; and He Himself does not, as some think, exist outside the world, but within it, being fully present throughout the entire universe, observing all generations; serving as the guiding force of all ages and the manager of His own powers and works, the first principle of everything, the light of heaven, and Father of all, the intelligence and life-giving spirit of the universe, the motion of all orbits.” Thus spoke Pythagoras.