is consistent with the general principles of the Shariah, as established in the chapters on riba.

It is also stipulated that this must not be used as a legal device for riba. If it is used as a device for riba, it is unlawful. For example, he may sell a debt that has fallen due in exchange for a larger deferred debt, saying: “You presently owe one hundred sa‘ of wheat, and the debt has fallen due, but you do not have it. I will sell it to you for one hundred sa‘ of dates on deferred payment.” Since one hundred sa‘ of dates are of greater value than one hundred sa‘ of wheat, this is not permissible, lest it become a device for rolling over the debt.

Thus, regarding the sale of a debt for a debt: if a creditor sells to the debtor himself what is owed by him, and it is of a type for which immediate possession is stipulated, possession must be taken. If immediate possession is not required, there is no harm in delaying possession, provided that the value is not increased because of the delay in taking possession.

For example, a man owes another one hundred riyals. The debtor comes and says: “I do not have one hundred riyals; rather, I have ten dinars, and each dinar is worth ten riyals.” The creditor says: “Give me ten dinars in exchange for the one hundred.” This is permissible, provided that possession is taken immediately, because it is an exchange of dirhams for dinars.

But if he says: “I do not have one hundred riyals, nor do I have dinars, but I have wheat, of which one sa‘ is worth one dirham. Thus, in place of one hundred dirhams, there will be one hundred sa‘.” He says: “I will give you one hundred sa‘ in exchange for one hundred dirhams,” and the creditor agrees, then immediate possession is not stipulated, because the exchange of wheat for dirhams does not require immediate possession, since they do not share the effective cause of riba al-fadl.

But if he says: “I accept wheat, but in exchange for the one hundred dirhams, give me one hundred