Good Manners and Form (Al-Adab)
Bukhari :: Book 8 :: Volume 73 :: Hadith 181
Narrated Abu Huraira:
Allah's Apostle saw a man driving a Badana (a camel for sacrifice) and said to him, "Ride on it." The man said, "O Allah's Apostle! It is a Bandana." The Prophet said, "Ride on it, woe to you!" on the second or third time.