Job 15:31

“Let not him that is deceived trust in vanity, etc.] Every wicked man is deceived, either by Satan, who deceives the whole world, deceived our first parents, and deceives all their posterity, not only profane sinners, but many professors of religion also; or by their own hearts, which are deceitful and desperately wicked; or through the deceitfulness of sin, which promises profit, pleasure, and liberty, and issues in ruin, pain, and bondage; and through the deceitfulness of riches, which promise that satisfaction they do not give: and such as are deceived in this manner are prone to trust in vanity; in men, who in every state, high or low, are altogether vanity; and in creature enjoyments, in…”

“Rather, "let him not trust in vanity or he will be deceived," &c. vanity--that which is unsubstantial. Sin is its own punishment (Pro 1:31; Jer 2:19).”

“Let not him that is deceived trust in vanity - The sense is, “Let him not trust in vanity. He will be deceived. Vanity will be his recompense.” The idea is, that a man should not confide in that which will furnish no support. He should not rely on his wealth and rank; his houses and lands; his servants, his armies, or his power, if he is wicked, for all this is vain. He needs some better reliance, and that can be found only in a righteous life. The word vanity here means that which is unsubstantial; which cannot uphold or sustain; which will certainly give way. For vanity will be his recompense - He will find only vanity. He will be stripped of all his honors and possessions. return to 'Top…”

“Vanity - In the vain and deceitful things of this world, he subjoins a general caution to all men to take heed of running into the same error and mischief. Vanity - Disappointment and dissatisfaction, and the loss of all his imaginary felicity. Recompence - Heb. his exchange; he shall exchange one vanity for another, a pleasing vanity for a vexatious vanity. Job 15:32”

“not him: Job 12:16; Isa 44:20; Gal 6:3, Gal 6:7; Eph 5:6 trust: Psa 62:10; Isa 59:4; Jon 2:8 for vanity: Job 4:8; Pro 22:8; Isa 17:10, Isa 17:11; Hos 8:7; Gal 6:8 Job 15:32”

“31 Let him not trust in evil-he is deceived, For evil shall be his possession. 32 His day is not yet, then it is accomplished, And his palm-branch loseth its freshness. 33 He teareth off as a vine his young grapes, And He casteth down as an olive-tree his flower. 34 The company of the hypocrite is rigid, And fire consumeth the tents of bribery. 35 They conceive sorrow and bring forth iniquity, And their inward part worketh self-deceit. אל does not merely introduce a declaration respecting the future (Luther: he will not continue, which moreover must have been expressed by the Niph.), but is admonitory: may he only not trust in vanity (Munach here instead of Dech, according to the rule of…”