except when the commodity is food or a relish; in that case it must be returned in the very measure or weight and in the same condition in which it was received. Even if the creditor has received food against his debt, then departs to fetch pack-animals or to rent premises in which to store it—so that a day or two elapse—or he begins to measure it, the sun sets, and he completes the measuring the next day, all such delays are unobjectionable according to Mālik and his companions.

A further example of replacing one debt with another is to defer payment of the salam capital until the salam term, or to a nearer or more distant date, as we explained in the chapter on salam. In my judgment it may not be postponed even for an hour, just like currency exchange; if it is nevertheless done, the contract must be rescinded and each party must recover whatever he has already handed over.

According to most of Mālik’s companions it is also “debt for debt” when, once a debt has fallen due, the creditor converts it into a house he will occupy, a slave who will serve him, a mount he will ride, fruit that must be harvested over several days, or a female slave for whom an istibrāʾ waiting period is required. A group of Mālik’s associates—among them Ashhab and Muḥammad ibn Maslama—do not count this as debt for debt, and in my view their position is the sounder analogy, for their unanimity on the permissibility of salam sales and of selling a salam obligation on credit shows that “debt for debt” applies only when both sides of the transaction consist solely of deferred obligations.

Among the transactions the Prophet likewise forbade is the townsman selling on behalf of the Bedouin. Mālik never differed over his disapproval of the townsman’s selling for the Bedouin, but he did differ concerning the townsman’s buying for him: on one occasion he said, “There is no harm in his purchasing for him; the prohibition relates only to selling on his behalf.”