[Another Chain]
Imam Aḥmad (1) said: ʿAffān narrated to us; Ḥammād ibn Zayd narrated to us; Yaḥyā ibn Saʿīd narrated to us, from Abū Umāmah ibn Sahl ibn Ḥanīf, who said:

I was with ʿUthmān in the house while he was under siege. We used to enter by a certain passageway, and whenever we went through it we could hear the voices of those standing on the paved courtyard. One day ʿUthmān went inside to attend to a need and then came out to us with his complexion changed. He said, “They have just been threatening to kill me.”

We replied, “Allah will suffice you against them, O Commander of the Believers.” He said, “But on what basis would they kill me? I heard the Messenger of Allah ﷺ say:

‘The blood of a Muslim is not lawful to shed except in one of three cases: a man who apostatizes after having embraced Islam, a married person who commits adultery, or one who kills another person without right.’

By Allah, I have never committed fornication—neither in the pre-Islamic period nor after Islam—nor have I ever wished to exchange my religion since Allah guided me to it, nor have I killed anyone. So on what grounds would they kill me?”

The four Sunan compilers (2) recorded this report as well, through Ḥammād ibn Zayd from Yaḥyā ibn Saʿīd, who said, “Abū Umāmah (3) related it to me….” Al-Nasāʾī added: “and ʿAbd Allāh ibn ʿĀmir ibn Rabīʿah, both of whom said, ‘We were with ʿUthmān,’” and he mentioned the remainder of the report. (Al-Tirmidhī declared it ḥasan, and Ḥammād ibn Salamah transmitted it from Yaḥyā ibn Saʿīd and raised it to a marfūʿ report.)

[Another Chain]
Imam Aḥmad (4) said: [Abū Qaṭan] narrated to us; Yūnus—meaning ibn Abī Isḥāq—narrated to us, from his father, from Abū Salamah ibn ʿAbd al-Raḥmān, who said:

ʿUthmān looked out from the fortress while he was under siege and said, “I adjure by Allah anyone who witnessed the Messenger of Allah ﷺ on the day of Ḥirāʾ, when the mountain shook and he struck it (5) with his foot, saying: ‘Be still, Ḥirāʾ; upon you are only a Prophet, a truthful one, or a martyr’—and I was with him—to bear witness.” Several men responded.

He then said, “I adjure by Allah anyone who witnessed the Messenger of Allah ﷺ on the day of the Pledge of Riḍwān, when he sent me to the idolaters in Mecca and said, ‘This is my hand and this is the hand of ʿUthmān’ (6) and pledged on my behalf, to bear witness.” Several men responded.

Then he said, “I adjure by Allah anyone who heard the Messenger of Allah ﷺ say: ‘Who will enlarge (7) this mosque for us by purchasing (8) that house of his…’”