C. F. Keil and Franz Delitzsch on Proverbs 12:11

Pro 12:11 11 He that tilleth his own ground is satisfied with bread,      And he that followeth after vain pursuits is devoid of understanding.

Yet more complete is the antithetic parallelism in the doublette, Pro 28:19 (cf. also Sir. 20:27a). The proverb recommends the cultivation of the field as the surest means of supporting oneself honestly and abundantly, in contrast to the grasping after vain, i.e., unrighteous means of subsistence, windy speculations, and the like (Fl.). ריקים are here not persons (Bertheau), but things without solidity and value (lxx μάταια; Aquila, Theodotion, κενά), and, in conformity with the contrast, not real business. Elsewhere also the mas. plur. discharges the function of a neut. noun of multitude, vid., נגידים, principalia, Pro 8:6, and זדים, Psa 19:14 - one of the many examples of the imperfect use of the gender in Hebr.; the speaker has in ריקים, vana et inania, not אנשׁים (Jdg 9:4), but דברים (Deu 32:47) in view. The lxx erroneously at Pro 28:19, and Symmachus and Jerome at both places understand ריקים of slothfulness.