Musnad Ahmad 33:372

Hajjaj narrated to us, from Ibn Jurayj, [who said]: Abu al-Zubayr informed me that he heard Jabir being asked about riding the sacrificial animal (*al-hady*). He said: I heard the Messenger of Allah, peace and blessings of Allah be upon him, say: "Ride it in a reasonable manner, when you are compelled to do so, until you find a mount."