Irenaeus

In his own words on Titus

• Titus 3:10

  But as many as separate from the Church, and give heed to such old wives' fables as these, are truly self-condemned; and these men Paul commands us, "after a first and second admonition, to avoid." And John, the disciple of the Lord, has intensified their condemnation, when he desires us not even to address to them the salutation of "good-speed;" for, says he, "He that bids them be of good-speed is a partaker with their evil deeds;" and that with reason, "for there is no good-speed to the ungodly," saith the Lord.

  Against Heresies Book I

• Titus 3:10

  There are also those who heard from him that John, the disciple of the Lord, going to bathe at Ephesus, and perceiving Cerinthus within, rushed out of the bath-house without bathing, exclaiming, "Let us fly, lest even the bath-house fall down, because Cerinthus, the enemy of the truth, is within." And Polycarp himself replied to Marcion, who met him on one occasion, and said, "Dost thou know me?" "I do know thee, the first-born of Satan." Such was the horror which the apostles and their disciples had against holding even verbal communication with any corrupters of the truth; as Paul also says, "A man that is an heretic, after the first and second admonition, reject; knowing that he that is such is subverted, and sinneth, being condemned of himself."

  Against Heresies Book III