was mentioned binding, such that payment becomes due merely upon conclusion of the contract. At most, if it is held to be permissible, it would be permissible in these circumstances.

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

A man sold a commodity at the going market rate, but a higher amount was subsequently demanded of him. The commodity has perished and is a fungible item. Is he entitled to recover an equivalent when one is available?

He replied:

He is not entitled to demand from him anything above the price prevailing when possession was taken, namely, the usual price of an equivalent item. Rather, what may be demanded is the price prevailing at that time, which is the value of an equivalent item.

There are two reported positions concerning the validity of this contract:

The first is that it is valid, just as a comparable arrangement is valid when hiring services: for example, when someone gives food to a person who cooks for payment, enters a bathhouse, or boards a ship. According to this position, the contract is valid and the stipulated amount is payable.

The second is that the contract is invalid, so the commodity has been received under an invalid contract. It may be argued that compensation must therefore be made with an equivalent if the commodity is fungible, and otherwise with its value, as in the case of wrongfully seized property. This is the position of a group of our scholars and others, including the Shāfiʿīs. Here, however, they have mutually agreed