Musannaf Ibn Abi Shayba 13:1371

Abu Bakr narrated to us, he said: Abbad bin al-Awwam narrated to us, from Hajjaj, from Atiyyah, from Ibn Umar: He said: I asked him about raisins, dates, wheat, and barley. He said: "There is no harm in it, but do not sell it until you have taken possession of it."