Bulugh al-Maram, Book 1, Hadith 85 (English)

Narrated Anas bin Malik (rad): The Prophet had blood extracted from his body and offered the prayer and did not perform (a new) ablution. [Reported by Ad-Daraqutni who graded it Da’if (weak)].

وَعَنْ أَنَسِ]بْنِ مَالِكٍ] ‏- رضى الله عنه ‏- { أَنَّ اَلنَّبِيَّ ‏- صلى الله عليه وسلم ‏-اِحْتَجَمَ وَصَلَّى, وَلَمْ يَتَوَضَّأْ } أَخْرَجَهُ اَلدَّارَقُطْنِيُّ, وَلَيَّنَه ُ (97)‏.‏ ‏3 ‏- ضعيف.‏ رواه الدارقطني (151‏-152)‏.‏

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also referenced under: Book 1, Hadith 96 (In-Book)