Wages (Kitab Al-Ijarah)
Dawud :: Book 23 : Hadith 3415
Narrated Muhayyisah ibn Ka'b:
Muhayyisah asked permission of the Apostle of Allah (peace_be_upon_him) regarding hire of the cupper, but he forbade him. He kept on asking his permission, and at last he said to him: Feed your watering camel with it and feed your slave with it.