The Book of Zakat
12/47. Chapter:
The Khawarij and their attributes
Sahih Muslim
حَدَّثَنَا شَيْبَانُ بْنُ فَرُّوخَ، حَدَّثَنَا الْقَاسِمُ، - وَهُوَ ابْنُ الْفَضْلِ الْحُدَّانِيُّ - حَدَّثَنَا أَبُو نَضْرَةَ، عَنْ أَبِي سَعِيدٍ الْخُدْرِيِّ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " تَمْرُقُ مَارِقَةٌ عِنْدَ فُرْقَةٍ مِنَ الْمُسْلِمِينَ يَقْتُلُهَا أَوْلَى الطَّائِفَتَيْنِ بِالْحَقِّ " .
Abu Sa'id al-Khudri reported that the Messenger of Allah (ﷺ) said: A group would secede itself (from the Ummah) when there would be dissension among the Muslims. Out of the two groups who would be nearer the truth would kill them.
Reference : Sahih Muslim 1065bIn-book reference : Book 12, Hadith 195USC-MSA web (English) reference : Book 5, Hadith 2325