Sahih Muslim | Book 34 | Hadith Number 6454

Narrated by Abu Wa'il
Abu Wa'il reported: I was sitting with 'Abdullah and Abu Musa that they reported Allah's Messenger (may peace be upon him) having said: Prior to the Last Hour, there would be a time when knowledge would be taken away, and ignorance would take its place and there would be bloodshed on a large scale.