and similar foods, Mālik—may Allah have mercy on him—and his followers differed as to whether unequal exchanges within a single kind were permissible.

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This disagreement led those identifying the legal cause to differ over its precise formulation. Those who permitted unequal exchanges of these foods added “ordinarily forming a basic source of sustenance” to their definition of the legal cause of ribā. Our teacher, the jurist Ibn Rizq—may Allah have mercy on him—held that this was the position adopted in al-Mudawwana, although I do not find it clearly established there. Those who prohibited unequal exchanges of these foods confined their definition to “food that is stored and used as a staple,” without adding “ordinarily forming a basic source of sustenance.” This is Mālik’s explicit position in his al-Muwatta’—may Allah have mercy on him—and Ibn Habīb’s position in al-Wādiha. It is also what appears to me to be the position in al-Mudawwana.

This distinction accounts for Mālik’s differing statements on the permissibility of unequal exchanges of eggs, and for the disagreement over the permissibility of unequal exchanges of figs, since both are stored but do not ordinarily form a basic source of sustenance. As for foods that are only rarely stored, such as peaches, pears, and similar foods, unequal exchanges within a single kind are permissible according to Mālik—may Allah have mercy on him—and most of his followers. As for foods that are not stored at all, unequal exchanges within a single kind are permissible according to Mālik—may Allah have mercy on him—and all his followers.

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As for exchanging food for food on deferred terms, or selling food before taking full delivery of it, neither is permissible under any circumstances, whether the kinds are the same or different, and whether or not the food is stored. It is Allah who grants success through His mercy.