Divine punishment for grave sins

إِنَّ ٱلَّذِينَ يَكْفُرُونَ بِـَٔايَـٰتِ ٱللَّهِ وَيَقْتُلُونَ ٱلنَّبِيِّـۧنَ بِغَيْرِ حَقٍّ وَيَقْتُلُونَ ٱلَّذِينَ يَأْمُرُونَ بِٱلْقِسْطِ مِنَ ٱلنَّاسِ فَبَشِّرْهُم بِعَذَابٍ أَلِيمٍ

Those who disbelieve in the signs of Allāh and kill the prophets without right and kill those who order justice from among the people - give them tidings of a painful punishment.