Chapter on Riba (Usury)

Riba is forbidden. Whenever a commodity that is ordinarily sold by volume or by weight is exchanged for the same kind with an excess, the prohibition applies. The operative cause is the combination of the relevant measure (volume or weight) with sameness of genus. Thus, if a measured or weighed commodity is bartered for its own kind on an equal basis, the sale is valid; if inequality occurs, it is invalid.

It is likewise impermissible to trade superior quality for inferior quality of the same commodity except on a like-for-like basis. If both determining factors—the shared genus and the accompanying attribute—are absent, disparity (tafāḍul) and deferment (nasīʾa) are both lawful. When both factors are present, both are unlawful. If one factor is present while the other is absent, disparity is permitted whereas deferment remains forbidden.

Any item with respect to which the Messenger of Allah ﷺ explicitly prohibited disparity on the basis of volume is permanently deemed a measure-based commodity—wheat, barley, dates, and salt—even if people no longer sell it by measure. Likewise, anything for which he banned disparity on the basis of weight is forever treated as a weight-based commodity, such as gold and silver. Whatever the texts do not specify follows people’s customary practice.

In a ṣarf (currency-exchange) contract, which deals with the genus of money, both counter-values must be taken into possession within the session. For other transactions that involve riba, mere specification is sufficient and actual mutual possession is not required. It is not permissible to sell wheat for flour or for roasted flour (sawīq).

According to Abū Ḥanīfa and Abū Yūsuf, it is permissible to sell meat for a live animal. Muḥammad rules that it is impermissible unless the meat contained in the animal is less than the quantity being purchased.

It is permissible to barter fresh dates for dried dates on an equal basis, and grapes for raisins; but it is not permissible to exchange olives for olive oil, nor sesame seed for sesame oil.

That exchange becomes lawful only when the quantity of oil or sesame oil offered exceeds the amount naturally found in the olives or sesame seeds, so that the oil is matched by its equivalent and the surplus accounts for the residual pulp.

It is lawful to trade different kinds of meat against one another with disparity, and likewise cow’s milk for sheep’s milk, vinegar made from inferior dates for grape vinegar, and bread for wheat and fat, all with disparity.

There is no riba between a master and his slave, nor between a Muslim and a belligerent non-Muslim when the transaction takes place in enemy territory.