Albert Barnes Commentary Job 18:21

"Surely such are the dwellings of the unrighteous, And this is the place of him that knoweth not God." — Job 18:21 (ASV)

Surely such are the dwellings of the wicked—this is the conclusion or sum of the whole matter. The meaning is that the habitations of all who did not know God would be desolate—a declaration Job could not help but regard as aimed at himself .

This is the end of this harsh and severe speech. It is no wonder that Job felt it keenly, and that he did feel it is apparent from the following chapter.

A string of proverbs had been presented, appearing as proof and stemming from long observation of the course of events. These proverbs evidently bore on his circumstances and were so pertinent to his condition that he could hardly deny their relevance. He was stung to the quick and gave vent to his agonized feelings in the following chapter.