Sahih Muslim
Sahih Muslim 1065 c
The Khawarij and their attributes
Arabic hadith text
حَدَّثَنَا أَبُو الرَّبِيعِ الزَّهْرَانِيُّ، وَقُتَيْبَةُ بْنُ سَعِيدٍ، قَالَ قُتَيْبَةُ حَدَّثَنَا أَبُو عَوَانَةَ، عَنْ قَتَادَةَ، عَنْ أَبِي نَضْرَةَ، عَنْ أَبِي سَعِيدٍ الْخُدْرِيِّ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم "تَكُونُ فِي أُمَّتِي فِرْقَتَانِ فَتَخْرُجُ مِنْ بَيْنِهِمَا مَارِقَةٌ يَلِي قَتْلَهُمْ أَوْلاَهُمْ بِالْحَقِّ "
Translation
Abu Sa'id al-Khudri reported Allah's Messenger (ﷺ) as saying
There would be two groups in my Ummah, and there would emerge another group (seceding itself from both of them), and the party nearer to the truth among the two would kill them (the group of the Khawarij).