Albert Barnes Commentary Job 20:10

"His children shall seek the favor of the poor, And his hands shall give back his wealth." — Job 20:10 (ASV)

His children shall seek to please the poor — The marginal note offers an alternative: “the poor shall oppress his children.” The idea in the Hebrew seems to be that his sons will be reduced to the humiliating condition of asking for aid from the most needy and abject. Instead of being in a position to assist others and to indulge in liberal hospitality, they themselves will be reduced to the necessity of applying to the poor for the means of subsistence. There is great strength in this expression. It is usually regarded as humiliating to be compelled to ask for aid at all; but the idea here is that they would be reduced to the necessity of asking for it from those who themselves needed it, or, as it implies, “would be beggars of beggars.”

And his hands shall restore their goods — Noyes renders this, “And their hands shall give back his wealth.” Rosenmuller supposes it means, “And their hands shall restore his iniquity;” that is, what their father took unjustly away. There can be little doubt that this refers to his “sons,” and not to himself, even though the singular suffix in the word (ידיו yâdāŷ), “his hands,” is used. However, the singular is sometimes used instead of the plural. The word rendered “goods,” (און 'ôn), means “strength, power, and then wealth.” The idea here is that the hands of his sons would be compelled to give back the property that the father had unjustly acquired. Instead of retaining and enjoying it, they would be compelled to make restitution and thus be reduced to poverty and want.