Hadith
أَخْبَرَنَا إِسْحَاقُ بْنُ مَنْصُورٍ، قَالَ أَنْبَأَنَا عَبْدُ الرَّحْمَنِ، عَنْ سُفْيَانَ، عَنِ الأَعْمَشِ، عَنْ عَبْدِ اللَّهِ بْنِ مُرَّةَ، عَنْ مَسْرُوقٍ، عَنْ عَبْدِ اللَّهِ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " وَالَّذِي لاَ إِلَهَ غَيْرُهُ لاَ يَحِلُّ دَمُ امْرِئٍ مُسْلِمٍ يَشْهَدُ أَنْ لاَ إِلَهَ إِلاَّ اللَّهُ وَأَنِّي رَسُولُ اللَّهِ إِلاَّ ثَلاَثَةُ نَفَرٍ التَّارِكُ لِلإِسْلاَمِ مُفَارِقُ الْجَمَاعَةِ وَالثَّيِّبُ الزَّانِي وَالنَّفْسُ بِالنَّفْسِ " . قَالَ الأَعْمَشُ فَحَدَّثْتُ بِهِ إِبْرَاهِيمَ فَحَدَّثَنِي عَنِ الأَسْوَدِ عَنْ عَائِشَةَ بِمِثْلِهِ .
It was narrated that 'Abdullah said:"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
Sahih · Abu Ghuddah
Sunan an-Nasa'i 4016 ·Book 37, Hadith 51·Also available on sunnah.com·