By Him in Whose hand is my soul, a time would come upon the people when the killer would not know why he killed and the victim would not know why he was killed
Authentic hadithعن أبي هريرة، قال: قال النبي صلى الله عليه وسلم : «والذي نفسي بيده ليأتينَّ على الناس زمانٌ لا يدري القاتلُ في أيِّ شيء قَتَل، ولا يدري المقتولُ على أيِّ شيء قُتِل».
Abu Hurayrah (may Allah be pleased with him) reported that the Prophet (may Allah's peace and blessings be upon him) said: ''By Him in Whose hand is my soul, a time would come upon the people when the killer would not know why he killed and the victim would not know why he was killed.''
Explanation
The Prophet (may Allah's peace and blessings be upon him) swears by Allah that there will come a time when murder would be so widespread that the killer would not know the reason he killed and the killed would not know the reason he was killed for.
Source · Narrated by Muslim
From the Hadith Encyclopedia (hadeethenc.com).