by which its quantity is measured and ascertained. Moreover, this involves a rationale appropriate to prohibiting unequal exchange.

If it is said, “Commodities measured by volume or weight are equivalent, and the reason for the prohibition is the absence of equivalence,” the response is:

No rational person sells something for its equivalent with deferred payment. He may, however, lend something in order to receive its equivalent after a time. Lending is a gratuitous act, akin to lending an item for use, as the Prophet, may Allah bless him and grant him peace, called it:

“A gratuitous loan of silver or a gratuitous loan of gold.”

When property is handed over to someone who enjoys its benefit for a period and then returns it to its owner, the owner has freely granted its benefit for that period, although each type has its own name. In the case of a palm tree, it is called a loan for use; in the case of an animal whose milk is drunk, a loan for its milk. The recipient may then return the very same property, if that particular property is what is intended; otherwise, he returns its equivalent.

The particular dirhams themselves are not what is intended. Thus, the borrower’s returning their equivalent is like the manager in a profit-sharing partnership returning their equivalent, namely, the capital. This is why it is called a loan, and why the lender is entitled only to the equivalent of his property. He may not stipulate any increase over it, whatever the type of property, by scholarly agreement.

The lender is entitled to the equivalent of his loan in its qualities, just as he is entitled to an equivalent when his property is wrongfully seized or destroyed. No rational person would sell something for an equivalent of this kind. Something is sold for its like only when its qualities differ.

The Lawgiver sought to disregard differences in quality when exchanging money. He therefore intended dirhams to be exchanged for an equal weight of dirhams, without regard to differences in their qualities, even when each individual dirham is light in weight. This is what someone does when seeking lightweight dirhams, either to give them to oppressors or to make payments with them