Musannaf Ibn Abi Shayba 21:603

Waki’ narrated to us, from Usama bin Zayd, from Muhammad bin Hamza bin ‘Amr, from his father, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Upon the hump of every camel is a devil. So when you ride them, mention the name of Allah, and make them subservient, for indeed Allah carries."