C. F. Keil and Franz Delitzsch on Proverbs 28:21

Pro 28:21

With a proverb, in the first half of which is repeated the beginning of the second appendix, Pro 24:23, a new group commences: 21 Respect of persons is not good;      And for a morsel of bread a man may become a transgressor.

Line first refers to the administration of justice, and line second - the special generalized - to social life generally. The “morsel of bread,” as example of a bribe by means of which the favour of the judge is purchased, is too low a conception. Hitzig well: “even a trifle, a morsel of bread (1Sa 2:36), may, as it awakens favour and dislike within us, thus in general call forth in the will an inclination tending to draw one aside from the line of strict rectitude.” Geier compares A Gellius’ Noct. Att. i. 15, where Cato says of the Tribune Coelius: Frusto panis conduci potest vel ut taceat vel ut loquatur.