Hadith: 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

عن 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».
[صحيح] - [رواه مسلم]

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.''
Sahih/Authentic. - [Muslim]

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.