Job 31:16

If I have withheld the poor from their desire, or have caused the eyes of the widow to fail;

Job 31:16 belongs to the debate between Job and his three friends about his afflictions, which spans Job 4-31.
It is part of Job's defense of his conduct, moral integrity, and uprightness, in which he denies withholding the poor from their desire or what they needed and denies causing the eyes of the widow to fail, to lose hope, to wait until hope failed through neglect, or to despair.
It is part of his challenge that God should judge him if any moral stain is found in his conduct.
Care for the poor and widows is presented here as evidence of integrity and as part of a strong declaration about general care for the needy.

Job was one of the richest men of his day yet did not sin by being rich, because he did not trust in his riches or rejoice because his wealth was great, but trusted in the living God and remembered that God gives power to get wealth.
He looked upon his wealth always only as a means of blessing the poor, the needy, the fatherless, and the widow, holding all subject to God's call, ready to distribute and willing to communicate, without putting confidence in riches or becoming proud and highminded because of them.

Paying debts to others alone does not prove a person is honest, since failing to help the needy is also a mark of wrongdoing.