Musnad Ahmad 830:28

Yahya ibn Sa'id narrated to us, from 'Uyaynah, my father narrated to us, he said: I went out for the funeral of 'Abd al-Rahman ibn Samurah. He said: Some men from his family began to face the funeral procession and walk backwards, saying: "Slowly, may Allah bless you." He said: Abu Bakrah caught up with us from the direction of al-Mirbad. When he saw those people and what they were doing, he charged at them with his mule and gestured toward them with his whip, and said: "Move aside! For by the One who honored the face of Abu al-Qasim (peace be upon him), I have seen us with the Messenger of Allah (peace be upon him) and we would almost be jogging with it [the funeral procession]." Yahya said once: "I have seen us with the Messenger of Allah (peace be upon him)."