Musnad Ahmad 30:2980

Yahya narrated to us, from Zakariya, who said: Amir narrated to me, from Abu Hurayrah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "The back [of the animal] is ridden for its maintenance when it is pledged as collateral, and the milk of the nursing animal is drunk when it is pledged as collateral. And upon the one who drinks and rides is its maintenance."