Sunan Abi Dawud, Hadith 3423 ⓘ
Narrated Ibn 'Abbas: The Messenger of Allah got him self cupped and gave the cupper his wages. Had he considered it impure, he would not have given it (wage) to him.
حَدَّثَنَا مُسَدَّدٌ، حَدَّثَنَا يَزِيدُ بْنُ زُرَيْعٍ، حَدَّثَنَا خَالِدٌ، عَنْ عِكْرِمَةَ، عَنِ ابْنِ عَبَّاسٍ، قَالَ احْتَجَمَ رَسُولُ اللَّهِ صلى الله عليه وسلم وَأَعْطَى الْحَجَّامَ أَجْرَهُ وَلَوْ عَلِمَهُ خَبِيثًا لَمْ يُعْطِهِ .
also referenced under: Hadith 3416 (Hasan)