حَدَّثَنَا أَحْمَدُ بْنُ سِنَانٍ، حَدَّثَنَا يَزِيدُ بْنُ هَارُونَ، عَنْ سُلَيْمَانَ التَّيْمِيِّ، وَسَعِيدِ بْنِ أَبِي عَرُوبَةَ، عَنْ قَتَادَةَ، عَنِ الْحَسَنِ، عَنْ أَبِي مُوسَى، قَالَ قَالَ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ ‏"‏ إِذَا الْتَقَى الْمُسْلِمَانِ بِسَيْفَيْهِمَا فَالْقَاتِلُ وَالْمَقْتُولُ فِي النَّارِ ‏"‏ ‏.‏ قَالُوا يَا رَسُولَ اللَّهِ هَذَا الْقَاتِلُ فَمَا بَالُ الْمَقْتُولِ قَالَ ‏"‏ إِنَّهُ أَرَادَ قَتْلَ صَاحِبِهِ ‏"‏ ‏.‏

It was narrated from Abu Musa that the Messenger of Allah (PBUH) said: “When two Muslims confront one another with their swords, both thekiller and the slain will be in Hell.” They said: “O Messenger ofAllah, (we understand about) this killer, but what is wrong with theone who is slain?” He said: “He wanted to kill his companion.’” Translation Not Available

Book Ref: Sunan Ibn Majah Book 36 Hadith 3964
Web Ref:  Sunan Ibn Majah Vol 5 Book 36 Hadith 3964