It is narrated from Hazrat Abu Huraira that he said: The Messenger of Allah, peace and blessings be upon him, said: "Trials (fitnah) will become numerous and killing (harj) will become widespread." We asked, "What is harj?" He, peace and blessings be upon him, said: "Killing." And knowledge will decrease. He said: "This (knowledge) will not be taken out from the hearts of people, but knowledge will decrease due to the death of scholars."