356.Narrated Abu Huraira (Allah be pleased with him): The Prophet (peace be upon him) said, "(Religious) knowledge will be taken away (by the death of religious scholars) ignorance (in religion) and afflictions will appear; and Harj will increase." It was asked, "What is Harj O Allah's Apostle (peace be upon him) ?" He replied by beckoning with his hand indicating "killing."
(Sahih Al-Bukhari Vol 1).
(Dr. Muhammad Muhsin Khan et.al.).