Titus 2:1 - Dummelow's Commentary on the Bible

Sound doctrine] cp. Titus 2:2, 'sound in faith.' The context shows that this is soundness not in intellectual opinions, but in the inculcation of uprightness of life. In Christ's day 'faith' was always regarded as spiritual; in the apostolic age, nearly always so; but in the apostolic age the tendency unquestionably began to identify 'faith' with a system. It is important to mark that faith and doctrine as used in this Epistle are not far from the earlier use: cp. Intro. § 2.