Bulugh al-Maram, Book 6, Hadith 30 (In-Book)

Ibn 'Abbas (RAA) narrated, ‘The Messenger of Allah had himself cupped while he was in the state of Ihram Agreed upon.

وَعَنِ اِبْنِ عَبَّاسٍ رَضِيَ اَللَّهُ عَنْهُمَا; أَنَّ اَلنَّبِيَّ ‏- صلى الله عليه وسلم ‏-{ اِحْتَجَمَ وَهُوَ مُحْرِمٌ } مُتَّفَقٌ عَلَيْهِ 1‏.‏ ‏1 ‏- صحيح.‏ رواه البخاري ( 1835 )‏، ومسلم ( 1202 )‏.‏

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also referenced under: Book 6, Hadith 756 (English)