To Florus 6.28

What, finally, will be said about the serpent itself? Do you think that curse punished the devil or this ordinary crawling animal? The pronouncement says to the serpent: ‘You are cursed beyond all cattle and all beasts upon the earth. You shall go upon your breast and belly and eat earth all the days of your life’ (Genesis 3:14). Do you think it was fulfilled in the devil’s punishment, or in the beast that spring warmth draws out of its holes?

If in this serpent, whose form stretches into a body without joints, and if you say that fault’s desert made it an earth-eater, then inherited iniquity burdens all beasts too. You think such transmission can occur only through the desire of those coupling. It follows that you must assert the devil planted the desire of serpents and hence of irrational animals. With your position exposed, you will blare Mani’s tune at us.

But if you acknowledge that everything said to the serpent was fulfilled spiritually in the devil, you will undoubtedly agree that the punishment spoken there neither proves present-day serpents guilty nor means the devil bodily eats earth. Even if he then enlisted the serpent’s service, and fatherly severity afterward broke it like the weapon he had used to wound humanity, sin still remained solely in the agent’s will.

Foods, thorns, and sweat were first established naturally, afterward increased judicially in certain cases, and have reached our own age [without that sin itself being passed on]. These matters are so plain that they require no lengthy defense.