It is narrated from Sayyiduna Abu Sa'id Khudri (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him and his family) forbade buying the unborn offspring of livestock before they are born, buying milk in the udders without measuring it, buying a runaway slave, buying spoils of war before they are distributed, buying charity before taking possession of it, and trading by divers.