وَحَدَّثَنَا ابْنُ أَبِي عُمَرَ الْمَكِّيُّ، حَدَّثَنَا مَرْوَانُ، عَنْ يَزِيدَ، - وَهُوَ ابْنُ كَيْسَانَ - عَنْ أَبِي حَازِمٍ، عَنْ أَبِي هُرَيْرَةَ، قَالَ قَالَ النَّبِيُّ صلى الله عليه وسلم ‏"‏ وَالَّذِي نَفْسِي بِيَدِهِ لَيَأْتِيَنَّ عَلَى النَّاسِ زَمَانٌ لاَ يَدْرِي الْقَاتِلُ فِي أَىِّ شَىْءٍ قَتَلَ وَلاَ يَدْرِي الْمَقْتُولُ عَلَى أَىِّ شَىْءٍ قُتِلَ ‏"‏ ‏.‏

Abu Huraira reported Allah's Messenger (PBUH) as saying: By Him in Whose Hand is my life, a time would come when the murderer would not know why he has committed the murder, and the victim would not know why he has been killed. Translation Not Available

Book Ref: Sahih Muslim Book 54 Hadith 6949
Web Ref:  Sahih Muslim Book 41 Hadith 2908 a