Bulugh al-Maram, Book 9, Hadith 1213 (English)

Ibn 'Umar (RAA) narrated that The Messenger of Allah said: “If a man holds another man so that a third man can kill the seized one, then the one who killed is to be killed (in Qisas) and the one who seized the killed one is to be imprisoned.” Related by Ad-Daraqutni. Ibn al-Qattan graded it as Sahih and its narrators are trustworthy.

وَعَنْ اِبْنِ عُمَرَ رَضِيَ اَللَّهُ عَنْهُمَا, عَنْ اَلنَّبِيِّ ‏- صلى الله عليه وسلم ‏-قَالَ: { إِذَا أَمْسَكَ اَلرَّجُلُ اَلرَّجُلَ, وَقَتَلَهُ اَلْآخَرُ, يُقْتَلُ اَلَّذِي قَتَلَ, وَيُحْبَسُ اَلَّذِي أَمْسَكَ } رَوَاهُ اَلدَّارَقُطْنِيُّ مَوْصُولًا وَمُرْسَلًا, وَصَحَّحَهُ اِبْنُ اَلْقَطَّانِ, وَرِجَالُهُ ثِقَاتٌ, إِلَّا أَنَّ اَلْبَيْهَقِيَّ رَجَّحَ اَلْمُرْسَلَ 1‏.‏ ‏1 ‏- صحيح.‏ وهو مخرج في " الأقضية النبوية " لابن الطلاع ص ( 8 منسوختي )‏.‏

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also referenced under: Book 9, Hadith 1183 (In-Book)