Amr bin Dinar عمرو بن دينار الأثرم الجمحي · The Book of Fighting [The Prohibition of Bloodshed]

"Abu Bakr became infuriated with a man." He said: "If you tell me to, I will do it." He said: "By Allah, that is not for any human being after Muhammad ."

"Abu Bakr got very angry with a man, so much so that his color changed. I said: 'O Khalifah of the Messenger of Allah, if you tell me to, I will strike his neck (kill him).' It was as if cold water had been poured on him and he became calm. He said: 'May your mother be bereft of you, Abu Barzah! That is not for anyone after the Messenger of Allah .'"

The Prophet said: "Do not revert to misguidance after I am gone, striking the necks of one another (killing one another)."