Musnad Ahmad 32:1471

Abu Qatan narrated to us, Hisham narrated to us, from Qatadah, from Anas ibn Malik, who said: The Messenger of Allah, peace and blessings of Allah be upon him, came upon a man driving a sacrificial camel. He said: "Ride it." The man said: "It is a sacrificial camel." He said: "Ride it." The man said: "It is a sacrificial camel." He said: "Ride it, woe to you" or "Woe unto you."