It is narrated from Sayyiduna Abu Umamah bin Sahl (may Allah be pleased with him) that during the days when Sayyiduna Uthman (may Allah be pleased with him) was besieged in his house, we were with him. He said, "For what crime will these people kill me? When I have heard the Prophet (peace and blessings of Allah be upon him) say that it is not lawful to shed the blood of a Muslim except in one of three cases: a man who becomes an apostate after accepting Islam, or a married person who commits adultery, or a murderer who is killed in retaliation for the one he killed."