What is the ruling on transactions involving goods subject to Riba (usury) when exchanged by weight, like grain, if one item is found defective?
Chapter on Selling the Musarrah (Animal with milk retained in udder)
Al-Mughni
Book of Sales
Primary text
If one measure (*qafiz*) of grain, subject to the prohibition of unequal exchange (*riba*), is exchanged for its like, and one of them is found defective in a way that reduces its value but not its measure, the receiver is not permitted to claim compensation (*arsh*) to avoid leading to unequal exchange. The ruling in this matter follows what was stated concerning silver jewelry exchanged for dirhams.
Supporting text
This transaction is governed by the principle that demanding *arsh* would lead to unequal exchange in a transaction requiring exact equality.