مُسْنَدُ أَحْمَدَ
Musnad Ahmad 4277
Musnad of Abdullah bin Mas'ood
It was narrated that Shaqeeq said: I was with ‘Abdullah and Abu Moosa, and they were narrating hadeeth. They narrated that The Messenger of Allah (ﷺ) said: "Ahead of the Hour there will be days in which knowledge will be taken away and ignorance will prevail, and there will be a lot of harj.“ They said: Harj means killing.
Musnad Ahmad 4306Its isnad is saheeh, Muslim (2672)]