It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "A believer does not kill by treacherous surprise attack (fatk); faith has restrained treacherous killing." This hadith is sahih (authentic) on the condition of Imam Muslim, but the two Shaykhs (Bukhari and Muslim) did not record it.

It is narrated from Marwan bin al-Hakam: I went in with Sayyiduna Mu'awiyah (may Allah be pleased with him) to the Mother of the Believers, Sayyidah Aishah (may Allah be pleased with her), and she said: O Mu'awiyah! You killed Hujr and his companions and did what you did. Do you not fear that I might hide a man in wait who would kill you? He replied: No, I am in a house of safety. I heard the Messenger of Allah (peace and blessings be upon him) say: "Faith has restrained treacherous killing; a believer does not kill treacherously."

It is narrated from Amr bin Ghalib that Sayyiduna Ammar (may Allah be pleased with him) came to Sayyidah Aishah (may Allah be pleased with her) on the day of the Battle of the Camel and said: Peace be upon you, O my mother! She said: I am not your mother. Ammar said: Rather, you are my mother, even if you dislike it. Sayyidah Aishah asked: Whose voice is this that I hear with you? He said: Al-Ashtar's. The Lady said: O Ashtar! Are you the one who wanted to kill my sister's son? Al-Ashtar said: I tried my utmost to kill him and he tried to kill me, but we were not able to. The Lady said: By Allah! Had you killed him, you would never have succeeded. Then she said: O Ammar! You know well that the Messenger of Allah (peace and blessings be upon him) said: "No one is to be killed except one of three: a man who killed someone and is killed in retaliation for him, a married person who commits adultery, and one who turns away from Islam." This hadith has an authentic chain (sahih al-isnad), but the two Shaykhs (Bukhari and Muslim) did not record it.