To Florus 3.154

Thus between you and Mani there is no disagreement about nature’s character, only about its author. You charge to God, whom you acknowledge as infants’ creator, the same evil Mani charges to the prince of darkness, whom he considered human nature’s maker. Little obstacle remains to renewing your alliance. Soon, however, I shall show that although neither of you shows any trace of truth, his statements agree with one another better than yours do.

What do we say? Undoubtedly something opposed to both of you: neither did the good God make an evil nature, nor did the prince of darkness make or mix another nature. Rather, the one God, author of all things, not only made human nature good at first but also makes it good in every newborn child. Yet we profess the help of its Creator to be both useful in many ways and necessary to it. The making of creatures is one matter and gifts another; and the work is not valued more highly here than the craftsman.

Both you and Mani therefore equally establish natural evil: you both call human nature evil, but he does so more consistently, you more deceitfully. Both of you suppose this evil was breathed by the devil into human inward parts. He exempts no one’s birth from it. You, however, to seem different in some way—although there is no difference—try to exempt just two human beings. Yet you do not free even their persons from sin. With the advance of a more learned intelligence, you say that what you persuade us became natural through them was not natural in them. So, lest your fraud escape punishment even here, the added stupidity punished the theft you committed against your teacher. To believe natural what you admit was adopted by the will is an invention not merely of an uneducated mind but of a drunken one. More about this elsewhere; for now, let us press the matter.

Mani maintains that evil is natural; you agree. He says sins are born; you consent. He says human nature is evil; you confirm this too. He says the nature of absolutely everyone; here you resist, asking that the first pair be set aside. Yet you do not vindicate even them from guilt; rather, you affirm that they originated natural evil. Even if we could indulge you in this, your teacher will not. Perhaps he will even punish your slow intelligence with a schoolmaster’s rod, forcing you either to submit to his authority or to leave his school altogether. Finally he draws his conclusion: an evil nature cannot have a good author. Therefore humanity, which both of you acknowledge to be naturally evil, is the work of the prince of darkness, that is, the devil.