Musnad Ahmad 30:232

Sufyan narrated to us, from Abu al-Zinad, from Musa ibn Abi Uthman, from his father, from Abu Hurayrah—or from al-A'raj, from Abu Hurayrah—that 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." The man said, "It is a sacrificial camel." He said, "Ride it, woe to you." And he did not express doubt about it once, and he said: From Musa ibn Abi Uthman, from his father, from Abu Hurayrah.