no one sells one dirham for two. This is why lending is prescribed here, for it is an act of generosity.

Since the prevalent form of usury—the one first addressed by the Quran and commonly practised by people—is usury involving deferment, it was said:

“Usury is only in deferred exchange.”

Moreover, usury involving unequal amounts was prohibited only because it leads to usury involving deferment. Thus, the usury primarily intended by the prohibition is usury involving deferment, so there is no usury except in it. Usury is most clearly evident in exchanges within a single kind of identical quality: when someone sells a hundred dirhams for a hundred and twenty, it is clear that the additional amount is in return for the period of deferment, which provides no benefit and is accepted only out of need. For this reason, periods of deferment are not compensable on grounds of either possession or destruction. Thus, if the property remained in someone’s possession, or the sum remained a debt he owed, for a period of time, he would not be liable to compensate for that period. This differs from an enhancement in quality, which is compensable in cases of destruction and wrongful seizure, and in a sale when exchanged for something of a different kind.

This is a broad subject. A declarative statement is either an affirmation or a negation. Just as people, when affirming, apply a name to something in which the intended meaning of that name is realized—even if the outward form of what it designates is absent—so too when negating. Negating particles indicate that a name does not apply because what it designates is absent. This may be because it does not exist at all; or because the essential reality intended by the designation is absent; or because that reality is incomplete; or because what is designated is not something that ought to be sought as an end, but rather something else should be sought.