713 – Jabir ibn ʿAbd Allah (may Allah be pleased with him) reported: “The Messenger of Allah (peace and blessings be upon him) forbade selling a heap of dates whose exact measure is unknown for a specified, measured amount of dates.” Related by Muslim. (1)

714 – Maʿmar ibn ʿAbd Allah (may Allah be pleased with him) said: “I used to hear the Messenger of Allah (peace and blessings be upon him) say, ‘Food for food must be like for like,’ and in those days our food was barley.” Related by Muslim. (2)

Glossary of the two ḥadiths
• subrah (pl. subar): a pile or heap of food, so called because part of it is poured out on top of the rest. Ibn Durayd said, “I bought the food as a subrah,” meaning without any measure or weight.
• shaʿīr (barley): a cereal grass of the gramineous family, nutritionally inferior to wheat.

Points derived from these ḥadiths
1 – It is forbidden to exchange unequal amounts when the two items are of the same genus among commodities subject to ribā; according to the stronger view, this applies to every foodstuff sold by measure or weight. Ḥadith 712 is explicit regarding dates, and every other measured commodity is treated the same. Al-ʿAynī said: “All food falls under the ruling of dates; within a single genus neither excess nor deferred payment (nasāʾ) is permissible by unanimous agreement.”