From his father, that he sought permission from the Prophet ﷺ to take the wages for cupping and he ﷺ forbade him from it. He continued asking him and seeking his permission until he said: "Use it to give fodder to your water-carrying camels, and to feed your slaves." [He said:] There are narrations on this topic from Rafi' bin Khadij, Abu Juhaifah, Jabir, and As-Sa'ib bin Yazid.  

أَنَّهُ اسْتَأْذَنَ النَّبِيَّ ﷺ فِي إِجَارَةِ الْحَجَّامِ فَنَهَاهُ عَنْهَا فَلَمْ يَزَلْ يَسْأَلُهُ وَيَسْتَأْذِنُهُ حَتَّى قَالَ اعْلِفْهُ نَاضِحَكَ وَأَطْعِمْهُ رَقِيقَكَ قَالَ وَفِي الْبَابِ عَنْ رَافِعِ بْنِ خَدِيجٍ وَأَبِي جُحَيْفَةَ وَجَابِرٍ وَالسَّائِبِ بْنِ يَزِيدَ  

Malik related to me from Ibn Shihab from Ibn Muhayyisa al-Ansari, one of the Banu Haritha, that he asked permission from the Messenger of Allah ﷺ to give payment for cupping, and he forbade him to do it. He continued to ask and seek his permission until he said, "Feed the ones who drive your water-carrying camels," meaning "your slaves."  

أَنَّهُ اسْتَأْذَنَ رَسُولَ اللَّهِ ﷺ فِي إِجَارَةِ الْحَجَّامِ فَنَهَاهُ عَنْهَا فَلَمْ يَزَلْ يَسْأَلُهُ وَيَسْتَأْذِنُهُ حَتَّى قَالَ اعْلِفْهُ نُضَّاحَكَ يَعْنِي رَقِيقَكَ  

Muhayyisah asked permission of the Messenger of Allah ﷺ 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. (Using translation from Abū Dāʾūd 3422)   

أَنَّهُ اسْتَأْذَنَ رَسُولَ اللهِ ﷺ فِي إِجَارَةِ الْحَجَّامِ فَنَهَاهُ عَنْهَا فَلَمْ يَزَلْ يَسْأَلْهُ فِيهَا حَتَّى قَالَ لَهُ اعْلِفْهُ نَاضِحَكَ وَأَطْعِمْهُ رَقِيقَكَ