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

An insolvent man obtained wheat on credit from another man at several times its value. Its price remained unchanged from the time he obtained it until payment fell due. The creditor supplied it on credit, described its qualities, and stated that each irdabb (a measure of grain) was worth sixteen. He drew up a deed, and they agreed on a price of thirty-two per irdabb. The debtor sold it, with supporting evidence and witnesses, for twelve dirhams per irdabb, contrary to the description given by the borrower. Payment has now fallen due, and the debtor is unable to meet the demand for payment. Should he be required to pay its fair market value, the amount recorded against him, or wheat equivalent to the wheat supplied?

He replied:

An insolvent person may not be pressed to pay what he cannot afford. Even if the debt is rightfully due, he must be granted respite. If the transaction is usurious, only the principal may be demanded. Selling a specific item that is not present, without describing it, is an invalid sale: the item or its equivalent must be returned, and the seller is not entitled to the stipulated price.

How much more so if he says, “This is currently worth such-and-such, and I will sell it to you on credit for such-and-such a higher amount”? This is usury. As Ibn ‘Abbās—may Allah be pleased with him—said:

“If you value it at the cash price and sell it for cash, there is no harm; but if you value it at the cash price and sell it on credit