Narrated to us Abu Bakr ibn Abi Shaybah, and Abu Kurayb, and Ishaq ibn Ibrahim — Ishaq said: "We were informed," while the other two said: "Narrated to us Waki', from Sufyan, from Ibn Tawus, from his father, from Ibn 'Abbas, who said: The Messenger of Allah (peace be upon him) said: 'Whoever buys food, let him not sell it until he has taken possession of it by measure.' I said to Ibn 'Abbas: 'Why?' He said: 'Do you not see that they are transacting with gold while the food is deferred?' Abu Kurayb did not say 'deferred.'"