John Gill Bible Commentary

Should he reason with unprofitable talk?.... That is, the wise man, such a man as Job; does it become him to talk such idle stuff? that which is false, and foolish, and frothy, that does not minister grace to the hearer, and is not for the use of edifying; as whatever is untrue, unwise, vain, and empty, must be useless and answer no good end; nothing is profitable but what tends to increase solid wisdom and spiritual knowledge, and to exercise grace, and influence an holy life; wherefore what are profitable to the souls of men are the doctrines of the word of God, and the experiences of the grace of God, communicated by his people one to another; and nothing but these, or what agrees with them, should come out of the mouth of a wise and good man; nor can such an one expect to convince men of their errors, or reprove them for their sins with success, who deals in words of no profit: or with speeches wherewith he can do no good? but may do a great deal of hurt both to himself and others; but the same thing is here signified in different words,