Bakr ibn Haritha

Dhahabi: Bakr b. Haritha al-Juhani narrated a hadith to al-Hasan b. Bashir b. Malik b. Nafidh b. Malik al-Juhani, who said: My father narrated to me from his father, that he heard his grandfather say, who said: Bakr b. Haritha al-Juhani narrated to me, who said: I was in a raid led by the Messenger of Allah, may Allah bless him and grant him peace, and we fought the polytheists. I killed a polytheist and he sought refuge in Islam. I killed him, and this was reported to the Prophet, may Allah bless him and grant him peace, who became angry with me and ordered me to be removed. Then Allah revealed to him: 'It is not for a believer to kill a believer except by mistake.' He said: The Prophet, may Allah bless him and grant him peace, forgave me and brought me closer.

It was narrated by Ibn Mandah and Abu Nu'aym.