Musnad Ahmad 26:64

Abu Mu'awiyah narrated to us, Al-A'mash narrated to us, from Shaqiq, from Abdullah, who said: It is as if I am looking at the Messenger of Allah (peace and blessings of Allah be upon him) imitating a prophet whom his people struck, so he was wiping the blood from his face and saying: "My Lord, forgive my people, for they do not know."