The Prophet ﷺ 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 Messenger of Allah ﷺ?" He replied by beckoning with his hand indicating "killing." (Fath-al-Bari Page 192, Vol. 1)
عَنِ النَّبِيِّ ﷺ قَالَ يُقْبَضُ الْعِلْمُ وَيَظْهَرُ الْجَهْلُ وَالْفِتَنُ وَيَكْثُرُ الْهَرْجُ قِيلَ يَا رَسُولَ اللَّهِ وَمَا الْهَرْجُ فَقَالَ هَكَذَا بِيَدِهِ فَحَرَّفَهَا كَأَنَّهُ يُرِيدُ الْقَتْلَ