Despiseth his own soul - That is constructively; for if the instruction lead to the preservation of life and soul, he that neglects or despises it throws all as much in the way of danger as if he actually hated himself.

He that refuseth instruction,.... The instruction of parents, masters, ministers, and of God himself; or "correction" (y), instruction either by the word or by the rod; he that withdraws himself from it, will not be in the way of it, that shuns, neglects, and despises it, or carelessly and contemptuously attends it:
despiseth his own soul; shows that he makes no account of it, has no regard for it or care about it, when it is so precious a jewel, and the loss of it irreparable; not that a man can strictly and properly despise his soul, but comparatively, having a greater regard for his body, and especially for his carnal lusts and pleasures, than for that; or as a man diseased and refuses proper medicines may be said to despise his health;
but he that heareth reproof getteth understanding; or "a heart" (z); he gets understanding by listening to reproof, and behaving according to it; he better understands himself and his case, what he should shun and avoid, what he should receive, embrace, and do; instead of losing his soul, as the man that refuses correction does, he finds the life of it, and possesses it, and with it a large share of experience and spiritual wisdom.
(y) "correctionem", Pagninus, Vatablus; "qui abstrahit se a castigatione", Piscator. (z) "cor", Pagninus, Piscator, Schultens, Michaelis.

Sinners undervalue their own souls; therefore they prefer the body before the soul, and wrong the soul to please the body.

refuseth--or, "neglects," "passes by" (Proverbs 1:25; Proverbs 4:15).
despiseth . . . soul--so acts as if esteeming its interests of no value.

Two proverbs with the catchword מוּסר:
32 He that refuseth correction lightly values his soul;
But he that heareth reproof getteth understanding.
Regarding פּורע מוּסר, vid., Proverbs 13:18, cf. Proverbs 1:25, and מואס נפשׁו, Proverbs 8:36. נפשׁו contains more than the later expression עצמו, self; it is equivalent to חיּיו (Job 9:21), for the נפשׁ is the bond of union between the intellectual and the corporeal life. The despising of the soul is then the neglecting, endangering, exposing of the life; in a word, it is suicide (10b). Proverbs 19:8 is a variation derived from this distich: "He who gains understanding loves his soul," according to which the lxx translate here ἀγαπᾷ ψυχὴν αὐτοῦ. לב the Midrash explains by חכמה שׁנתונה בלב; but the correct view is, that לב is not thought of as a formal power, but as operative and carried into effect in conformity with its destination.