Holding fast the faithful word - That is, the true doctrines of the gospel. This means that he is to hold this fast, in opposition to one who would wrest it away, and in opposition to all false teachers, and to all systems of false philosophy. He must be a man who is firm in his belief of the doctrines of the Christian faith, and a man who can be relied on to maintain and defend those doctrines in all circumstances; compare notes, 2 Thessalonians 2:15.
As he hath been taught - Margin, “in teaching.” Greek “According to the teaching.” The sense is, according to that doctrine as taught by the inspired teachers of religion. It does not mean as he had individually been taught; but he was to hold the faith as it was delivered by those whom the Saviour had appointed to make it known to mankind. The phrase “the doctrine,” or “the teaching,” had a sort of technical meaning, denoting the gospel as that which had been communicated to mankind, not by human reason, but by teaching.
That he may be able by sound doctrine - By sound teaching, or instruction; Notes, 1Ti 1:10; 1 Timothy 4:16. He was not to dictate, or to denounce; but to seek to convince by the statement of the truth; see the notes at 2 Timothy 2:25.
Both to exhort and to convince - To persuade them, or to bring them over to your views by kind exhortation, and by the instruction which shall convince. The former method is to be used where men know the truth, but need encouragement to follow it; the latter, where they are ignorant, or are opposed to it. Both exhortation and argument are to be used by the ministers of religion.
The gainsayers - Opposers Literally, those who speak against; that is, against the truth; Notes, Romans 10:21.