John Gill's Exposition of the Whole Bible
Proverbs 14:30
A sound heart [is] the life of the flesh,.... A heart made so by the grace of God, in which are sound principles of truth, righteousness, and holiness; these preserve from sin, and so from many diseases; whereby the life of the flesh or body is kept safe and sound, or that is kept in health and vigour; or a "quiet heart" h; a heart free from wrath, anger, and envy, and such like passions and perturbations; this contributes much to the health of the body, and the comfort of life: or a "healing heart", or "spirit" i; that is humane, kind, and friendly; that pities and heals the distresses of others, and makes up differences between persons at variance: such an one is "the life of fleshes" k, as in the original text; or of men, of the same flesh and blood; the life of others, as well as of his own flesh; such an one contributes to the comfortable living of others as well as of himself;
but envy the rottenness of the bones; a man that envies the happiness and prosperity of others, this preys upon his own spirits, and not only wastes his flesh, but weakens and consumes the stronger parts of his body, the bones; it is as a "moth" within him, as the Arabic version: the Targum is,
"as rottenness in wood, so is envy in the bones;''
hence Ovid l calls it "livor edax", and so Martial m.
h לב מרפא "cor leve", Baynus; "cor lene", Mercerus; "cor lenitatis", Gejerus, so Ben Melech. i "Animus sanans", Junius Tremellius, so the Tigurine version "sanator", Gussetius, p. 800. k חיי בשרים "vitae carnium", Montanus; "vita carnium", V. L. Pagninus, Michaelis. l Amorum, l. 1. Eleg. 15. v. 1. de Remed. Amor. l. 1. in fine. m Epigr. l. 11. Ep. 21.