was practiced by the people of the pre-Islamic era: a man would hold a deferred debt against another; when the term fell due, the creditor would say to the debtor, “Either settle what you owe, or pay usury (turbi).” If the debtor paid, the matter ended; if he could not, the creditor would grant an extension and the debtor would add an increment, until the sum kept doubling and redoubling. Concerning this Allah the Exalted said: “O you who believe, do not consume usury, doubled and multiplied” (Āl ʿImrān 3:130).
The ideal course laid down by the Law is to grant respite to an insolvent debtor, as Allah says: “If the debtor is in hardship, then grant him respite until ease” (al-Baqarah 2:280).
When Allah commanded giving respite to the insolvent and forbade compound usury, scheming usurers turned instead to the practice known as “qalb al-dayn” (turning the debt over). This occurs when the debt falls due and the debtor is unable to pay; the creditor brings a sum of money, sells it to the debtor for foodstuffs or other goods on credit, then immediately takes that very money as payment in the same session.
Shaykh ʿAbd al-Raḥmān ibn Saʿdī said: “The most severe form of usury is qalb al-dayn, and it is among the major sins.”
Today usury has become blatant in the form of bank interest. A bank extends a loan to a needy applicant—whether an investment loan or a consumer loan—and then charges him an additional amount in return for the deferment; this is nothing other than plain, unequivocal ribā. Likewise, the interest paid on bank deposits, which constitutes the primary source of a bank’s income, squarely falls within the forbidden ribā, for it is the very essence of usury.
Islamic juristic councils have reached consensus that such interest is prohibited and is ribā in all three of its classical categories: ribā al-faḍl (surplus exchange), ribā al-nasīʾah (deferment), and ribā al-qarḍ (loan-based usury).
Here are excerpts from the statements of some of those councils:
The Council of the Islamic Fiqh Academy affiliated with the Organization of the Islamic Conference, in its second session held in Jeddah on 10/6/1406 AH, after reviewing the submitted research, declared