The Prescription Against Heretics

On this point, however, we dwell no longer, since it is the same Paul who, in his Epistle to the Galatians, counts “heresies” among “the sins of the flesh,” who also intimates to Titus, that “a man who is a heretic” must be “rejected after the first admonition,” on the ground that “he that is such is perverted, and commits sin, as a self-condemned man.” Indeed, in almost every epistle, when enjoining on us (the duty) of avoiding false doctrines, he sharply condemns heresies.

Of these the practical effects are false doctrines, called in Greek heresies, a word used in the sense of that choice which a man makes when he either teaches them (to others) or takes up with them (for himself). For this reason it is that he calls the heretic self-condemned, because he has himself chosen that for which he is condemned. We, however, are not permitted to cherish any object after our own will, nor yet to make choice of that which another has introduced of his private fancy.

In the Lord's apostles we possess our authority; for even they did not of themselves choose to introduce anything, but faithfully delivered to the nations (of mankind) the doctrine which they had received from Christ. If, therefore, even “an angel from heaven should preach any other gospel” (than theirs), he would be called accursed by us. The Holy Ghost had even then foreseen that there would be in a certain virgin (called) Philumene an angel of deceit, “transformed into an angel of light,” by whose miracles and illusions Apelles was led (when) he introduced his new heresy.