"You shall not sleep while holding his security"—Deuteronomy 24:12.
It is forbidden for a creditor to withhold a debt's collateral from its owner, the debtor, when he cannot do without it due to his poverty (see Positive Commandment 199). Rather he must return the collateral to him—an item used during the daytime must be returned for the duration of every day, and an item used at night must be returned for the duration of every night. As the Mishnah says, "He must return the pillow at night and the plow for the day."
