Musnad Abu Ya'la al-Mawsili 109:205

Narrated to us Abdullah ibn Amir ibn Zurarah, narrated to us Ibn Abi Za'idah, from Ibn Jurayj, from Abu al-Zubayr, from Jabir, who said: I heard the Prophet, peace and blessings of Allah be upon him, saying: "Ride it in a recognized manner if you are compelled to do so, until you find a mount," meaning by it the sacrificial camel.