Sahih Bukhari
Afflictions and the End of the World
Volume: 009 / Book Number: 088 / Hadith Number: 184
Narrated 'Abdullah and Abu Musa:
The Prophet said, "Near the establishment of the Hour there will be days during which Religious ignorance will spread, knowledge will be taken away (vanish) and there will be much Al-Harj, and Al-Harj means killing."