Sahih al-Bukhari 6868
Book 87: Blood Money (Ad-Diyat) · Narrated by `Abdullah bin `Umar
Arabic
حَدَّثَنَا أَبُو الْوَلِيدِ، حَدَّثَنَا شُعْبَةُ، قَالَ وَاقِدُ بْنُ عَبْدِ اللَّهِ أَخْبَرَنِي عَنْ أَبِيهِ، سَمِعَ عَبْدَ اللَّهِ بْنَ عُمَرَ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ " لاَ تَرْجِعُوا بَعْدِي كُفَّارًا يَضْرِبُ بَعْضُكُمْ رِقَابَ بَعْضٍ ".
English translation
Narrated `Abdullah bin `Umar:The Prophet (ﷺ) said, "After me (i.e. after my death), do not become disbelievers, by striking (cutting) the necks of one another
Reference: Sahih al-Bukhari 6868, Book of Blood Money (Ad-Diyat). English translation by Dr. Muhammad Muhsin Khan.