Sahih al-Bukhari 2279
صحيح البخاري#2279Sahihحَدَّثَنَا مُسَدَّدٌ، حَدَّثَنَا يَزِيدُ بْنُ زُرَيْعٍ، عَنْ خَالِدٍ، عَنْ عِكْرِمَةَ، عَنِ ابْنِ عَبَّاسٍ ـ رضى الله عنهما ـ قَالَ احْتَجَمَ النَّبِيُّ صلى الله عليه وسلم وَأَعْطَى الْحَجَّامَ أَجْرَهُ، وَلَوْ عَلِمَ كَرَاهِيَةً لَمْ يُعْطِهِ.
Narrated Ibn `Abbas:When the Prophet (ﷺ) was cupped, he paid the man who cupped him his wages. If it had been undesirable he would not have paid him
Scholarly Authentication
The label above is the grade most of these scholars gave — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. Each scholar's own wording:
Every narration in Sahih al-Bukhari is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 37:19