Musnad Ahmad 626:74

Waki’ and Rawh narrated to us, they said: Sa’id ibn ‘Ubayd Allah al-Thaqafi narrated to us, Rawh said: the son of Jubayr ibn Hayyah, he said: my paternal uncle Ziyad ibn Jubayr narrated to me, and Waki’ said: from Ziyad ibn Jubayr ibn Hayyah, from his father, from al-Mughirah ibn Shu’bah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "The rider [should be] behind the funeral procession, and the walker [may be] wherever he wishes from it, and the child—prayer is performed over him."