Sayyiduna Abu Hurairah (may Allah be pleased with him) narrated from the Messenger of Allah (peace and blessings be upon him), he (peace be upon him) said: "Knowledge will be taken away, tribulations will appear, and killing will become widespread." We asked him: What is killing? He (peace be upon him) said: "Killing." When Umar bin Khattab (may Allah be pleased with him) heard the statement of the Prophet (peace be upon him): "Knowledge will be taken away," he said: "The disappearance of knowledge does not mean that it will be taken out from the hearts of the people, rather the ending of knowledge is due to the passing away of the scholars."