Titus 3:10

“A man that is an heretic, etc.] An heretic, according to the notation of the word, is either one that makes choice of an opinion upon his own judgment, contrary to the generally received sense of the churches of Christ, and prefers it to theirs, and obstinately persists in it; separates from them, forms a party, and sets himself at the head of them, whom he has drawn into the same way of thinking with himself: or he is one that removes and takes away a fundamental doctrine of Christianity, which affects particularly the doctrine of the Trinity, the deity, and personality of Father, Son, and Spirit, and especially the doctrines relating to the person, office, and grace of Christ; one that…”

“heretic--Greek "heresy," originally meant a division resulting from individual self-will; the individual doing and teaching what he chose, independent of the teaching and practice of the Church. In course of time it came to mean definitely "heresy" in the modern sense; and in the later Epistles it has almost assumed this meaning. The heretics of Crete, when Titus was there, were in doctrine followers of their own self-willed "questions" reprobated in Tit 3:9, and immoral in practice. reject--decline, avoid; not formal excommunication, but, "have nothing more to do with him," either in admonition or intercourse.”

“A man that is an heretic - The word “heretic” is now commonly applied to one who holds some fundamental error of doctrine, “a person who holds and teaches opinions repugnant to the established faith, or that which is made the standard of orthodoxy.” Webster. The Greek word here used αἱρετικὸς hairetikos occurs nowhere else in the New Testament. The corresponding noun (αἵρεσις hairesis) occurs in the following places: Acts 5:17; Acts 15:5; Acts 24:5; Acts 26:5; Acts 28:22, where it is rendered “sect;” and Act 25:14; 1 Corinthians 11:19; Galatians 5:20; 2 Peter 2:1, where it is rendered “heresy,” and “heresies;” see the notes at Acts 24:14. The true notion of the word is that of one who is…”

“An heretic (after a first and second admonition) reject - Avoid, leave to himself. This is the only place, in the whole scripture, where this word heretic occurs; and here it evidently means, a man that obstinately persists in contending about "foolish questions," and thereby occasions strife and animosities, schisms and parties in the church. This, and this alone, is an heretic in the scripture sense; and his punishment likewise is here fixed. Shun, avoid him, leave him to himself. As for the Popish sense, "A man that errs in fundamentals," although it crept, with many other things, early into the church, yet it has no shadow of foundation either in the Old or New Testament. Titus 3:11”

“3:10-11 have nothing more to do with . . . people like that: This refers to incorrigibly quarrelsome and divisive people (see 1:11, 13).”

“heretic: Co1 11:19; Gal 5:20; Pe2 2:1 after: Mat 18:15-17; Co2 13:2 reject: Rom 16:17; Co1 5:4-13; Gal 5:12; Th2 3:6, Th2 3:14; Ti2 3:5; Jo2 1:10 Titus 3:11”