The Book of Transactions (Kitab Al-Buyu`)

Muslim :: Book 10 : Hadith 3654

Jabir b. Abdullah (Allah be pleased with them) is reported to have said that Allah's Messenger (may peace be upon him) forbade the sale of a heap of dates the weight of which is unknown in accordance with the known weight of dates.

Source materials are from the University of Southern California MSA site
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