Rafi reported from his father that he asked the Messenger of Allah ﷺ for permission regarding the earnings of a cupper, but the Prophet ﷺ forbade him from it. He kept asking and seeking permission until the Prophet ﷺ told him, "Use it as feed for your water-carrying camel and your slaves."
حدثنا عبد الله بن مسلمة القعنبي عن مالك عن ابن شهاب
عن أبيه أنه استأذن رسول الله ﷺ في إجارة الحجام فنهاه عنها فلم يزل يسأله ويستأذنه حتى أمره أن أعلفه ناضحك ورقيقك
[Sahih] Reported by Tirmidhi, Business Transactions, Chapter on What Has Been Said Regarding the Earnings of a Cupper, no. 1277, from the hadith of Malik, with this same chain, and he said, hasan sahih. Ibn Majah also reported it, no. 2166, and it is found in Muwatta (Yahya version), 2/974, where "from his father" was omitted, which is an error.