أَخْبَرَنَا عَلِيُّ بْنُ مُحَمَّدِ بْنِ عَلِيٍّ الْمِصِّيصِيُّ، قَالَ حَدَّثَنَا خَلَفٌ، عَنْ زَائِدَةَ، عَنْ هِشَامٍ، عَنِ الْحَسَنِ، عَنْ أَبِي بَكْرَةَ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ ‏"‏ إِذَا تَوَاجَهَ الْمُسْلِمَانِ بِسَيْفَيْهِمَا كُلُّ وَاحِدٍ مِنْهُمَا يُرِيدُ قَتْلَ صَاحِبِهِ فَهُمَا فِي النَّارِ ‏"‏ ‏.‏ قِيلَ لَهُ يَا رَسُولَ اللَّهِ هَذَا الْقَاتِلُ فَمَا بَالُ الْمَقْتُولِ قَالَ ‏"‏ إِنَّهُ كَانَ حَرِيصًا عَلَى قَتْلِ صَاحِبِهِ ‏"‏ ‏.‏

It was narrated from Abu Bakrah that : The Prophet [SAW] said: "If two Muslims confront each other with swords, each of them wanting to kill the other, they will both be in Hell." It was said to him: "O Messenger of Allah, (we understand about) the killer, but what about the one who is killed?" He said: "He was determined to kill his companion." Translation Not Available

Book Ref: Sunan An Nisai Book 37 Hadith 4120
Web Ref:  Sunan An Nisai Vol 5 Book 37 Hadith 4125