Musannaf Ibn Abi Shayba 13:1037

Abu Bakr narrated to us, he said: Hushaym narrated to us, from Hisham ibn Urwah, from his father, that some young boys from the Ansar had a young slave who was a cupper. The Prophet, may Allah bless him and grant him peace, commanded them to put his earnings into the fodder for the water-carrying camel.