Musnad Ahmad 32:1966

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