Sunan Abi Dawud, Hadith 2375

Narrated Anas: We would not allow a man who was fasting to get himself cupped due to abomination of hardship.

حَدَّثَنَا عَبْدُ اللَّهِ بْنُ مَسْلَمَةَ، حَدَّثَنَا سُلَيْمَانُ، - يَعْنِي ابْنَ الْمُغِيرَةِ - عَنْ ثَابِتٍ، قَالَ قَالَ أَنَسٌ مَا كُنَّا نَدَعُ الْحِجَامَةَ لِلصَّائِمِ إِلاَّ كَرَاهِيَةَ الْجَهْدِ ‏.‏

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also referenced under: Hadith 2369 (Hasan)