ACC ~ Titus 3 v11

THE NATURE OF HERESY. TERTULLIAN: 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.” This is on the ground that “he that 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 heresis, 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 in which he is condemned. ON PRESCRIPTION AGAINST HERETICS 6.

HIMSELF TO BLAME. CYPRIAN: The church cannot be rent or divided against itself. It maintains the unity of a single, indivisible house. … All who are to live and escape the destruction of the world must be gathered into one house alone, the church. If any of the gathered goes outside, that is, if anyone who once obtained grace in the church nevertheless abandons the church, his blood will be upon his head. He will have himself to blame for his damnation. The apostle Paul explains this, directing us to avoid a heretic as perverted, sinful and self-condemned. LETTERS 69.4.

SELF-EXCOMMUNICATED. MAXIMUS OF TURIN: For the heretic damns himself when he casts himself out of the Catholic church and under no compulsion leaves the gathering of the saints. He who separates himself from everyone by his own judgment shows what is merited from everyone. The heretic himself, I say, damns himself because, although all the wicked are cast out from the Christian assembly by the sentence of the bishop, the heretic departs himself, by the judgment of his own will, before anyone’s subsequent wishes are expressed. SERMONS 58.3.

Tit