Musnad Ahmad 658:68

Ibn Numayr narrated to us, al-A‘mash narrated to us, al-Minhal ibn ‘Amr narrated to us, from Abu ‘Umar Zadhan, who said: I heard al-Bara’ ibn ‘Azib say: We went out with the Messenger of Allah, may Allah bless him and grant him peace, for the funeral of a man from the Ansar. We reached the grave while it was not yet dug, so the Messenger of Allah, may Allah bless him and grant him peace, sat down, and we sat with him. He mentioned the like of it, and said: "Then he extracts it, and the veins and nerves are severed along with it." My father said: And Zaidah said likewise.