Abu Huraira reported Allah's Messenger (may peace be upon him) as saying: The world would not come to an end until a day would come to the people on which the murderer would not know as to why he has killed and the slain would not know as to why he has been murdered. It would be said: Why would It happen? To which he replied: It would be because of general massacre and bloodshed. - Sahih Muslim, book 41, hadith 6950
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