مِشْكَاةُ الْمَصَابِيحِ
Mishkat al-Masabih 3537
Retaliation
Killing Apostates and People who Strive to cause Mischief - Section 1
وَعَنْ جَرِيرٍ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ فِي حَجَّةِ الْوَدَاعِ: «لَا تَرْجِعُنَّ بَعْدِي كُفَّارًا يَضْرِبُ بَعْضُكُمْ رِقَاب بعض»
Jarir reported God’s Messenger as saying at the Farewell Pilgrimage, “You must never revert to infidelity after my death and cut off one another’s heads.” (Bukhari and Muslim.)
Mishkat al-Masabih, 3537مُتَّفَقٌ عَلَيْهِ (الألباني)