And Abu al-Qasim (peace be upon him) said: The Hour will not come until knowledge is taken away, tribulations will appear, and killing will become widespread. The companions (may Allah be pleased with them) asked: O Prophet of Allah! What is meant by killing? The Prophet (peace be upon him) said: Killing, killing.
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 7488