"The Messenger of Allah [SAW] said: 'By the One besides Whom there is no other god, it is not permissible to shed the blood of a Muslim who bears witness to La ilaha illalla (there is none worthy of worship except Allah) and that I am the Messenger of Allah, except in three cases: One who leaves Islam and splits away from the Jama'ah, a person who has been married and then commits adultery, and a life for a life.'" (Using translation from Nasāʾī 4016)

قَالَ رَسُولُ اللَّهِ ﷺ «وَالَّذِي لَا إِلَهَ غَيْرُهُ لَا يَحِلُّ دَمُ رَجُلٍ يَشْهَدُ أَنْ لَا إِلَهَ إِلَّا اللَّهُ وَأَنِّي رَسُولُ اللَّهِ إِلَّا ثَلَاثَةَ نَفَرٍ التَّارِكُ لِلْإِسْلَامِ الْمُفَارِقُ لِلْجَمَاعَةِ وَالثَّيِّبُ الزَّانِي وَالنَّفْسُ بِالنَّفْسِ» قَالَ الْأَعْمَشُ فَحَدَّثْتُ بِهِ إِبْرَاهِيمَ فَحَدَّثَنِي عَنِ الْأَسْوَدِ عَنْ عَائِشَةَ مِثْلَهُ