We were with Uthman while he was under siege. Whenever we entered a certain place, we could hear the words of those gathered at the courtyard. One day Uthman went in and then came out and said, "They are threatening to kill me."We said, "Allah will suffice you against them."He replied, "Why would they kill me? I heard the Messenger of Allah ﷺ say, 'The blood of a Muslim is not lawful except for one of three reasons, a man who disbelieves after his Islam, or commits adultery after marriage, or kills a soul other than in retaliation for a soul.' By Allah, I have never committed adultery, neither in the days of ignorance nor in Islam. I have never wished for any religion in place of mine since Allah guided me. And I have never killed anyone. So why would they kill me?"
أخبرني إبراهيم بن يعقوب قال حدثنا محمد بن عيسى قال حدثنا حماد بن زيد قال حدثنا يحيى بن سعيد قال
كنا مع عثمان وهو محصور وكنا إذا دخلنا مدخلا نسمع كلام من بالبلاط فدخل عثمان يوما ثم خرج فقال إنهم ليتواعدوني بالقتل قلنا يكفيكهم الله قال فلم يقتلوني سمعت رسول الله ﷺ يقول لا يحل دم امرئ مسلم إلا بإحدى ثلاث رجل كفر بعد إسلامه أو زنى بعد إحصانه أو قتل نفسا بغير نفس فوالله ما زنيت في جاهلية ولا إسلام ولا تمنيت أن لي بديني بدلا منذ هداني الله ولا قتلت نفسا فلم يقتلونني
Its isnad is sahih. Abu Dawud narrated it in "Diyat," chapter "The Leader Ordering Pardon in a Killing," no. 4502, from the hadith of Hammad bin Zayd, with the same wording. Tirmidhi narrated it, no. 2157, and said, "This is a hasan hadith." It is also in Kubra, no. 3482, and Ibn Jarud graded it sahih, no. 836.