The Book Pertaining to the Turmoil and Portents of the Last Hour (Kitab Al-Fitan wa Ashrat As-Sa`ah)
Muslim :: Book 41 : Hadith 6903
Abu Huraira reported Allah's Messenger (may peace be upon him) as saying: The last Hour will not come unless there is much bloodshed. They said: What is harj? Thereupon he said: Bloodshed. bloodshed.