Narrated Abu Sahlah:
"The day of the house (when he was besieged), 'Uthman said: 'Indeed the Messenger of Allah (ﷺ) took a covenant from me, and I will abide by it.'" (FR)
English reference (FR): Vol. 1, Book 46, Hadith 3711 (FR)
Arabic reference (FR): Book 49, Hadith 4076 (FR)