It is narrated from Abu Umamah bin Sahl bin Hunayf that Sayyiduna Uthman bin Affan (may Allah be pleased with him), (during the days of the siege), looked down from the roof of his house, addressed the people and said: "I ask you by Allah: do you know that the Messenger of Allah (peace and blessings be upon him) said: 'The blood of a Muslim is not lawful except in three cases: committing adultery after being married, or apostatising after accepting Islam, or unjustly killing a soul for which he is to be killed in retaliation'? So by Allah! I never committed adultery, neither in the Days of Ignorance (Jahiliyyah) nor in Islam; I have never apostatised since I pledged allegiance at the hand of the Messenger of Allah (peace and blessings be upon him); and I have never killed a soul that Allah has made sacred. So for what crime do you want to kill me?!" This hadith is sahih (authentic) on the condition of the two Shaykhs (Bukhari and Muslim), but they did not record it.