Musannaf Ibn Abi Shayba 21:602

Hatim ibn Isma'il narrated to us, from Ja'far, from his father, who said: The Messenger of Allah (may Allah bless him and grant him peace) said: "Upon the hump of every camel is a devil. So when you ride them, say as Allah has commanded you: 'Exalted is He who has subjected this to us, and we could not have [otherwise] subdued it.' And make them subservient for yourselves, for indeed Allah carries [you]."