Musnad Ahmad 32:1147

Yazid narrated to us, Shu'bah informed us, from Qatadah, from Anas, who said: The Messenger of Allah (peace and blessings of Allah be upon him) passed by a man who was driving a sacrificial camel. He said: "Ride it." The man said: "It is a sacrificial camel." He said: "Ride it, woe to you."