on credit, because both metals share the underlying cause of ribā. For that reason, each side must take possession in the very session where the contract is concluded; otherwise the ṣarf is invalid and turns into ribā al-nasīʾah (deferred usury).

Points derived from the ḥadīth:

1. It is forbidden to sell gold for silver—or silver for gold—when one or both counter-values are absent; hand-to-hand exchange in the contract session is indispensable.
2. The sale is sound when possession is exchanged in the same session, for the transaction is ṣarf.
3. What vitiates the contract in the absence of on-the-spot possession is the fact that the two currencies share the operative cause of ribā.
4. The report illustrates the scrupulous caution of the early generations—may Allah be pleased with them—and their habit of deferring to one another.

Hadith Five

From Abū Bakrah who said: “The Messenger of Allah ﷺ forbade silver for silver and gold for gold except [when exchanged] equal for equal. He commanded us to buy silver with gold however we wished and to buy gold with silver however we wished.” A man then asked, “Hand to hand?” He replied, “That is exactly what I heard.”

Overall meaning:
Because exchanging gold for gold or silver for silver with disparity constitutes ribā, the Prophet ﷺ prohibited it unless the two amounts are precisely equal, weight for weight. Exchanging gold for silver, or silver for gold, however, is permissible even when the amounts differ—provided that both parties take possession during the contract session; otherwise it becomes the forbidden ribā al-nasīʾah. The difference in genus allows disparity, but the shared riba-bearing cause keeps the requirement of immediate delivery in force.

Points derived from the ḥadīth:

1. Selling gold for gold or silver for silver with disparity is prohibited, because price and commodity fall within the same riba-bearing genus.
2. Exchanging gold for gold or silver for silver is permissible on two conditions:
   a. Exact equality, with neither amount exceeding the other.
   b. Immediate mutual possession in the contract session.
   What is said of gold and silver applies to every riba-bearing genus when part of it is exchanged for part of the same kind, such as wheat for barley.