Job 15:31 - Joseph Benson’s Commentary on the Old and New Testaments

Let not him that is deceived trust in vanity That is, in the vain and deceitful things of this world, such as power, riches, honour, &c., of which, and of the loss of them, he had been discoursing largely; and now he subjoins a general caution to all men to take heed of running into the same error and mischief with the fore-mentioned persons: and, withal, he secretly intimates what, he judged, had been Job's great sin, and the cause of his ruin, namely, his carnal confidence in those vain things, his wealth and glory, and the children which God had given him: from which crime Job, therefore, vindicates himself hereafter. For vanity Disappointment, dissatisfaction, and the loss of all his imaginary felicity; the same word vanity being elegantly repeated in another sense, as is usual in the Scripture, and all authors. Shall be his recompense Hebrew, תמורתו, temuratho, permutatio vel commutatio ejus; his exchange, Leviticus 27:33; he shall exchange one vanity for another, a pleasing vanity for a vexatious vanity. This verse however may be rendered otherwise, thus: He that is deceived with vanity (that is, with the vain things of this world, wherewith most men are deceived and bewitched) will not believe that vanity (namely, emptiness, disappointment, and misery) shall be his recompense. And thus this is an aggravation of his calamity, that it surprised him when he was confident, and secure from all fears of such an event.