Sahih Muslim Book 10, Hadith Number 3651.

Chapter : It is invalid to sell the commodity before taking possession of it.

Abu Huraira (Allah be pleased with him) reported Allah’s Messenger (may peace be upon him) as saying: He who bought food-grain should not sell it until he had measured it. In the narration of Abu Bakr there the word is Ibta’ instead of Ishtara.