Musannaf Ibn Abi Shayba 13:540

Abu Bakr narrated to us, he said: Hushaym narrated to us, from Abu Bishr, from Yusuf ibn Mahak, from Hakim ibn Hizam, who said: I said, "O Messenger of Allah, a man comes to me and asks me for a sale of something I do not possess. Should I sell it to him, then buy it for him from the market?" He said: "Do not sell what you do not possess."