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.'
It was narrated that 'Amr bin Ghalib said: Aishah said: 'Do you not know that the Messenger of Allah [SAW] said: It is not permissible to shed the blood of a Muslim, except a man who committed adultery after being married, or one who reverted to Kufr after becoming Muslim, or a life for a life.'
It was narrated that 'Amr bin Ghalib said: Aishah said: 'O 'Ammar! Do you not know that it is not permissible to shed the blood of a Muslim except in three cases: a life for a life, a man who commits adultery after being married.'
Abu Umamah bin Sahl and 'Abdullah bin 'Amir bin Rabi'ah said: We were with 'Uthman when he was under siege and we could hear what was said from Al-Balat. 'Uthman came in one day, then he came out, and said: 'They are threatening to kill me.' We said: 'Allah will suffice you against them.' He said: 'Why would they kill me? I heard the Messenger of Allah [SAW] say: It is not permissible to shed the blood of a Muslim except in one of three cases: A man who reverts to Kufr after becoming Muslim, or commits adultery after being married, or one who kills a soul unlawfully. By Allah, I did not commit adultery during Jahiliyyah or in Islam, I never wished to follow any other religion since Allah guided me, and I have never killed anyone, so why do they want to kill me?'