The Book of Zakat
12/47. Chapter:
The Khawarij and their attributes
Sahih Muslim
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 " .
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).
Reference : Sahih Muslim 1065cIn-book reference : Book 12, Hadith 196USC-MSA web (English) reference : Book 5, Hadith 2326