John Trapp on Job 21:19

Verſe 19. God layeth up his iniquity for his children] that is, the puniſhment of his iniquity, whilſt he viſiteth the ſins of the fathers upon the children to the third and fourth generation of them that hate him, Exod. 20.5. Neither doth this contradict that of the Prophet Ezekiel, The ſon ſhall not dye for the iniquity of his farher, chap. 18.17. Nor that of the Apoſtle, Every man ſhall bear his own burden, Gal. 5.6. for the meaning of thoſe worlds is, that no man be damned for the ſin of his father, nor one man for the ſin of another, unleſſe by commiſſion or approbation, or ſome way or other he make it his own. But for temporal puniſhments there is none but (by occaſion of others ſins) may have their portion in them: and wicked parents leave Jobs Legacy to their children (ſee 2 Sam. 3.29.) yea though they prove to be good children, 1 King. 14.12, 13. for whom God layeth up their parents iniquity in the treaſures of his juſtice to be produced in due time.

He rewardeth him.] For every tranſgreſſion and diſobedience; that is, every Commiſſion and Omiſſion, receiveth a juſt recompence of reward, Heb 2.2. God will abate him nothing.

And he ſhall know it.] Know it to his coſt; Vexation ſhall give underſtanding: he that before this judgement came, would know nothing of the bitter effect of ſin upon him and his, now hath his eyes forced open (as the blind Mole is ſaid to have by the pangs of death) and cryes out with the Lyon in the ſnare, Si praſciviſſem, Oh! if I had foreknown the miſchief, &c. The wicked are wiſe too late, the fool paſſeth on, and is puniſhed: he knows not the evil of ſin, till he feels it.