Sayyiduna Muhayyisah (may Allah be pleased with him) asked the Prophet (peace and blessings be upon him) about the earnings of the cupper, and he (peace and blessings be upon him) forbade it. He kept speaking to him (peace and blessings be upon him) until he (peace and blessings be upon him) said: "Feed your slave and give fodder to your animal."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الضحايا / 19506