C. F. Keil and Franz Delitzsch on Proverbs 16:8

Pro 16:8

Five proverbs of the king, together with three of righteousness in action and conduct: 8 Better is a little with righteousness,    Than rich revenues with unrighteousness.

The cogn. proverb Pro 15:16 commences similarly. Of רב תּבוּאות, multitude or greatness of income, vid., Pro 14:4 : “unrighteous wealth profits not.” The possessor of it is not truly happy, for sin cleaves to it, which troubles the heart (conscience), and because the enjoyment which it affords is troubled by the curses of those who are injured, and by the sighs of the oppressed. Above all other gains rises ἡ εὐσέβεια μετ ̓ αὐταρκείας (1Ti 6:6).