Musnad Ahmad 28:152

Abu Bakr al-Hanafi narrated to us, al-Dahhak bin Uthman narrated to us, from Amr bin Shu’ayb, from his father, from his grandfather, who said: "The Messenger of Allah (peace and blessings of Allah be upon him) forbade two transactions in one transaction, and a sale combined with a loan, and profiting from what one does not guarantee, and selling what you do not possess."