Titus 3:10

καὶ δευτέραν νουθεσίαν. This, the rec. reading, is supported by אACKLP and the great majority of MSS. and versions, and is indubitably the primitive reading; but the variants (νουθεσίαν καὶ [ἣ] δευτέραν D2cG g, and νουθεσίαν καὶ δύο D2*E d e) are curious, and point to early corruption. The various readings do not affect the meaning.

10. αἱρετικὸν ἄνθρωπον μετὰ μίαν καὶ δευτέραν νουθεσίαν παραιτοῦ. A man that is heretical after a first and second admonition avoid. We must be careful not to read into the adjective αἱρετικός all that it came to imply at a later stage of the Church’s life. The essence of the idea of αἵρεσις in St Paul (see 1 Corinthians 11:19; Galatians 5:20) is that wilful ‘choosing’ for oneself, which is the root of division and schism. The duty of the Christian teacher, in his view, is to ‘guard the deposit’ of doctrine which has been entrusted to him, and to refrain from vain and irrelevant speculations on matters where our only possible source of knowledge is revelation. The αἱρετικὸς ἄνθρωπος, on the other hand, is the man who is always trying to strike out a new line, and who is a cause of faction in the Church. αἱρετικός, thus, means rather ‘one who causes divisions’ than ‘one who holds false doctrine,’ a meaning which the word did not connote until a later date.

παραιτεῖσθαι (see on 1 Timothy 4:7) has no reference to anything like formal excommunication; the counsel here offered to Titus is simply to avoid persons who cause strife by their unedifying disputations and theories.