While I was with Mu'awiyah, two men came to him disputing over who killed 'Ammar. Each of them saying: I killed him. 'Abdullah ibn 'Amr said: Let one of you concede the matter to the other, for I heard the Messenger of Allah (PBUH) say: "He will be killed by the rebellious group". Mu'awiyah then said to 'Abdullah: Then why are you with us? 'Abdullah replied: My father complained about me to the Messenger of Allah (PBUH), so the Prophet (PBUH) said: Obey your father as long as he is alive and do not disobey him. So I am with you, but I do not fight.