is whatever they regard as a stipulation, just as a sale among them is whatever they regard as a sale, a lease is whatever they regard as a lease, and a marriage is whatever they regard as a marriage. Allah mentions sale, marriage and other matters in His Book, yet no definition of these has been given in religious law, nor do they have a definition in jurisprudence. The meanings of terms are sometimes defined by religious law, as with prayer, zakat, fasting and pilgrimage; sometimes by language, as with the sun, the moon, land and sea; and sometimes by custom, as with taking possession and separation. The same applies to contracts, such as sale, lease, marriage, gifts and others. Whenever people agree upon a stipulation and enter into a contract on that basis, it constitutes a stipulation according to customary usage.

He—may Allah have mercy on him—was asked:

A man sold another man barley on credit at sixty dirhams per sack, payable at a specified time. When payment fell due, he demanded it, but the debtor said, “I will give you nothing but barley.” Barley was then worth thirty dirhams per sack. May he accept barley or not?

He replied:

The scholars differ on this issue. The position of the Seven Jurists