حَدَّثَنَا عَبْدُ الرَّزَّاقِ حَدَّثَنَا مَعْمَرٌ عَنْ عَاصِمٍ الْأَحْوَلِ عَنِ الشَّعْبِيِّ عَنِ ابْنِ عَبَّاسٍ قَالَ حَجَمَ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ عَبْدٌ لِبَنِي بَيَاضَةَ وَأَعْطَاهُ النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ أَجْرَهُ وَلَوْ كَانَ حَرَامًا لَمْ يُعْطِهِ قَالَ وَأَمَرَ مَوَالِيَهُ أَنْ يُخَفِّفُوا عَنْهُ بَعْضَ خَرَاجِهِ
مسند امام احمد بن حنبل · Hadith 3457
It was narrated that Ibn 'Abbas (RA) said: The Prophet (PBUH) was treated with cupping by a slave belonging to Banu Bayadah, and the Prophet (PBUH) gave him his fee. If it were ha ram, he would not have given it to him. And he told his masters to reduce some of the share of his earnings (that they took).
Sanad
حَدَّثَنَا عَبْدُ الرَّزَّاقِ حَدَّثَنَا مَعْمَرٌ عَنْ عَاصِمٍ الْأَحْوَلِ عَنِ الشَّعْبِيِّ عَنِ ابْنِ عَبَّاسٍ