On the Morals of the Manichaeans

⁶ Now, compare with this perplexity, from which you cannot escape, the consistency of the statements in the teaching of the Catholic Church, according to which there is one good which is good supremely and in itself, and not by the participation of any good, but by its own nature and essence; and another good which is good by participation, and by having something bestowed. Thus it has its being as good from the supreme good, which, however, is still self-contained, and loses nothing.

This second kind of good is called a creature, which is liable to hurt through falling away. But of this falling away God is not the author, for He is author of existence and of being. Here we see the proper use of the word evil; for it is correctly applied not to essence, but to negation or loss. We see, too, what nature it is which is liable to hurt. This nature is not the chief evil, for when it is hurt it loses good; nor is it the chief good, for its falling away from good is because it is good not intrinsically, but by possessing the good.

And a thing cannot be good by nature when it is spoken of as being made, which shows that the goodness was bestowed. Thus, on the one hand, God is the good, and all things which He has made are good, though not so good as He who made them. For what madman would venture to require that the works should equal the workman, the creatures the Creator? What more do you want? Could you wish for anything plainer than this?