To Florus 4.77

But let us return to the case. You said I had been unwilling to name desire because “it is not from the Father but from the world. The devil is called the ruler of this world. He did not find it in the Lord, because the Lord came among human beings as a man without it” (Augustine, On Marriage and Concupiscence 2.26.41; compare 1 John 2:16; John 14:30). Notice this: you were speaking of a natural thing, and after saying it was from the world, you added that the devil should be believed ruler of the whole world. You were thus acknowledging him as author not of voluntary acts but of natural things—that is, of natures.