Musnad Ahmad 26:633

Muhammad ibn Ja'far narrated to us, Shu'bah narrated to us, from Wasil, from Abu Wa'il, from Abdullah, who said—and I think he attributed it to the Prophet, peace and blessings of Allah be upon him—that he said: "Before the Hour, there will be days of *al-harj* (turmoil), days in which knowledge will vanish and ignorance will appear." Abu Musa said: "*Al-harj*, in the Abyssinian language, means killing."