Jami` at-Tirmidhi 2158
جامع الترمذي#2158SahihAbu Umamah bin Sahl bin Hunaif narrated that on the day of siege, 'Uthman bin 'Affan stood overlooking the people, and he said:"I swear to you by Allah! You know that the Messenger of Allah (s.a.w) said: 'The blood of a Muslim man is not lawful, except for one of three (cases):Illegitimate sexual relations after Ihsan (having been married), or apostasy after Islam, or taking a life without right, for which he is killed.' By Allah! I have never committed illegitimate sexual relations, not during Jahiliyyah nor during Islam, and I have not committed apostasy since I gave my pledge to the Messenger of Allah (s.a.w), and I have not taken a life that Allah had made unlawful. So for what do you fight me?
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
In-book reference: 33:1