John Gill, on Prov 15:5

A fool despiseth his father's instruction,.... They are fools that despise any instruction that is wise, good, and profitable; and especially a father's instruction, whose love, tender affection, and care, will not suffer him, knowingly, to give any but what is good and wholesome: wherefore to despise it is not only a contempt of his authority, but a slight of his love; which are both very aggravating, and sufficiently demonstrate his folly; and of which he may be himself convinced when it is too late, and say, "how have I hated instruction and despised reproof?" Pro 5:12. He is a fool that despises the instruction of anyone superior to him in years and experience; of ministers of the word; and especially of our Father which is in heaven, declared in the sacred Scriptures, which are written for instruction in righteousness; but he that regardeth reproof is prudent; the reproof of a father, whose corrections are to be submitted to, and received with reverence; and especially of the Father of spirits, whose rebukes are in love, and for profit and advantage; yea, he is a wise man that regards the reproof of the word of God, and the ministers of it; and indeed of any Christian, whether his superior, equal, or inferior, as David did, Psa 141:5.