From Sahih Muslim (Hadith 3842):
Ibn Umar (Allah be pleased with them) reported Allah's Messenger (ﷺ) as saying:He who buys foodgrain should not sell that before taking possession of it. He (the narrator) said: We used to buy foodgrain from the caravans in bulk, but Allah's Messenger (ﷺ) forbade us to re-sell that until we had shifted it to some other place
Reference: Muslim 3842