To fill his belly to the full, God will send his burning anger against him and rain it upon him into his body.
Zophar, having described the many embarrassments and vexations which commonly attend the wicked practices of oppressors and cruel men, here comes to show their utter ruin at last. I. Their ruin will take its rise from God's wrath and vengeance, Job 20:23. The hand of the wicked was upon him (Job 20:22), every hand of the wicked.
Commenting on Job 20:23-29
When he is about to fill his belly,.... Either in a literal sense, when he is about to take an ordinary meal to satisfy nature; or in a figurative sense, when he is seeking to increase his worldly riches, and his barns and coffers, and endeavouring to get satisfaction therein: God shall cast the fury of his wrath upon him; or "send it out on...
Rather, "God shall cast (may God send) [UMBREIT] upon him the fury of His wrath to fill his belly!" while . . . eating--rather, "shall rain it upon him for his food!" Fiery rain, that is, lightning (Psa 11:6; alluding to Job's misfortune, Job 1:16).