Augustine of Hippo, on Matt 7:15

“Beware of false prophets, who come to you in the clothing of sheep, but inwardly they are ravening wolves.”

“(vid. Op. Imp. in. Jul. v. 40. &c. et alibi.) But as it is manifest that all evil works proceed from an evil will, as its fruits from an evil tree; so of this evil will itself whence will you say that it has sprung, except that the evil will of an angel sprung from an angel, of man from man? And what were these two before those evils arose in them, but the good work of God, a good and praiseworthy nature. See then out of good arises evil; nor was there any thing at all out of which it might arise but what was good. I mean the evil will itself, since there was no evil before it, no evil works, which could not come but from evil will as fruit from an evil tree. Nor can it be said that it sprung out of good in this way, because it was made good by a good God; for it was made of nothing, and not of God.”

Imported from an open dataset — not yet checked against the printed edition.