Musnad Ahmad 27:1304

Isma'il ibn 'Umar narrated to us, Sufyan narrated to us, from 'Awn ibn Abi Juhayfah, from 'Abd al-Rahman ibn Samurah: That Ibn 'Umar saw a head, and he said: The Messenger of Allah, peace and blessings of Allah be upon him, said: "What prevents one of you, when someone who wants to kill him comes to him, from being like the two sons of Adam: the killer in the Fire, and the killed in Paradise?"