Sunan an-Nasa'i, Hadith 4016 ⓘ
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.'"
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 .
also referenced under: Book 37, Hadith 51 (In-Book) & Volume 5, Book 37, Hadith 4021 (DarusSalam)