Musannaf Ibn Abi Shayba 13:1375

Abu Bakr narrated to us, he said: 'Abdah bin Sulayman narrated to us, from Yahya bin Sa'id, from Sa'id bin al-Musayyib, who said: "If you buy food, do not sell it until you take possession of it. And there is no harm in partnership, or [if] you give him the price."