Titus 1:6; Titus 1:9; Titus 3:8

6 namely, if any man is above reproach, the husband of one wife, having children who believe, not accused of dissipation or rebellion.
9 holding fast the faithful word which is in accordance with the teaching, so that he will be able both to exhort in sound doctrine and to refute those who contradict.
8 This is a trustworthy statement; and concerning these things I want you to speak confidently, so that those who have believed God will be careful to engage in good deeds. These things are good and profitable for men.