Sahih Muslim Book 41, Hadith Number 6949.

Chapter : The Last Hour would not come until a person would pass by a grave and wish that he should have been the occupant of that grave because of this calamity.

Abu Huraira reported Allah’s Messenger (may peace be upon him) 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.