Safwan bin Ya'la narrates from his father (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) appointed Attab bin Asid (may Allah be pleased with him) as governor of Makkah. He (peace and blessings be upon him) said: "I have made you the leader over the people of Allah, (enjoining you) with the fear of Allah." None of them should eat from the profit of something for whose loss he has not taken responsibility; and forbid them "from (combining) a loan and a sale, from two conditions in one sale, and that any one of them should sell what he does not have."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب البيوع / 10681