He reported God’s Messenger as saying, “The proviso of a loan combined with a sale is not allowable, nor two conditions relating to one transaction, nor the profit arising from something which is not in one’s charge (An article belongs to the seller till the transaction is complete, and so long as it is still in his possession he is the one who gains any profit on it or bears any loss. The buyer cannot claim profit till he is in possession of the article nor selling what is not in your possession.
Tirmidhi, Abu Dawud and Nasa’i transmitted it, Tirmidhi saying this is a sahih tradition.
Hakim b. Hizam said God's Messenger forbade him to sell anything which was not in his possession.
Tirmidhi transmitted it.
In a version by Abu Dawud and Nasa’i, he had said, “Messenger of God, a man comes to me and wants me to sell him something, but I do not have it and so I buy it for him from the market.” He replied, “Do not sell what you do not possess.”