Sunan Ibn Majah
4050
Sahih+3

It was narrated from ‘Abdullah that the Messenger of Allah (ﷺ) said:“Just before the Hour, there will be days when knowledge will disappear, ignorance will become widespread and there will be much Harj. And Harj means killing.”

SahihAl-Albani
SahihMuhammad Fouad Abd al-Baqi