When thou with rebukes dost correct man for iniquity. The calamities which God sends on a man are of the nature of "rebukes" addressed to his spirit. They are intended to teach, instruct, warn, deter from evil-doing (see Job 36:8-10).
Thou makest his beauty to consume away like a moth; or, "thou dost consume, as by a moth, what he prizes;" i.e. his health, his strength, "all wherein he has joy and satisfaction" (Hengstenberg). As a moth corrodes a beautiful garment, so does thy displeasure and heavy hand pressing on him corrode and destroy all which constituted his delight and glory.
Surely every man is vanity (comp. Psalms 39:5 ad fin.). This has become a sort of refrain, terminating the second as well as the first part of the psalm (comp. Psalms 107:8, Psalms 107:15, Psalms 107:21, Psalms 107:31; Ecclesiastes 2:1, Ecclesiastes 2:11, Ecclesiastes 2:15, Ecclesiastes 2:19, Ecclesiastes 2:21, Ecclesiastes 2:23, Ecclesiastes 2:26; Isaiah 9:12, Isaiah 9:17, Isaiah 9:21).