Sunan an-Nasa'i, Hadith 4130 ⓘ
It was narrated from Abu Bakrah that: The Prophet [SAW] said: "Do not revert to misguidance after I am gone, striking the necks of one another (killing one another)."
أَخْبَرَنَا عَمْرُو بْنُ زُرَارَةَ، قَالَ أَنْبَأَنَا إِسْمَاعِيلُ، عَنْ أَيُّوبَ، عَنْ مُحَمَّدِ بْنِ سِيرِينَ، عَنْ أَبِي بَكْرَةَ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ " لاَ تَرْجِعُوا بَعْدِي ضُلاَّلاً يَضْرِبُ بَعْضُكُمْ رِقَابَ بَعْضٍ " .
also referenced under: Book 37, Hadith 165 (In-Book) & Volume 5, Book 37, Hadith 4135 (DarusSalam)