The son of Rafi' bin Khadij (may Allah be pleased with him) relates from his father; he said: "The Messenger of Allah (peace and blessings be upon him) forbade us from something that was beneficial to us — and the command of the Messenger of Allah (peace and blessings be upon him) is upon our heads and eyes. He (peace and blessings be upon him) forbade us from having land worked in return for part of its produce or for fixed silver coins, and he also forbade us from the earnings of the cupper."
Hadith Referenceالمعجم الكبير للطبراني / باب الراء / 4338