It is narrated from Hazrat Amr bin Shu'aib that the Holy Prophet (peace and blessings be upon him) sent Hazrat Attab bin Asid (may Allah be pleased with him) to the people of Makkah and said: Do you know where I have sent you? I have sent you to the people of Allah. Then he said: Forbid them from four things: from sale and loan together, from stipulating two conditions in one sale, from using the profit of something for which he is not also liable for loss (i.e., as long as there is no participation in both profit and loss, profit cannot be used), and from selling something which is not in one's possession.