Adam Clarke on Job 20:10

His children shall seek to please the poor - They shall be reduced to the lowest degree of poverty and want, so as to be obliged to become servants to the poor. Cursed be Ham, a servant of servants shall he be. There are cases where the poor actually serve the poor; and this is the lowest or most abject state of poverty.

His hands shall restore their goods - He shall be obliged to restore the goods that he has taken by violence. Mr. Good translates: His branches shall be involved in his iniquity; i.e., his children shall suffer on his account. "His own hands shall render to himself the evil that he has done to others." - Calmet. The clause is variously translated.