Musannaf Ibn Abi Shayba 28:966

Waki’ narrated to us, he said: Al-Mas’udi narrated to us, from Muzahim ibn Zufar al-Taymi, from a man, from Khabbab, who said: Horses are three: a horse for Allah, a horse for you, and a horse for the devil. As for the horse that is for Allah, it is the horse that is used for fighting in the way of Allah. As for the horse that is for you, it is the horse that a man keeps for his own needs. As for the horse that is for the devil, it is that which is gambled upon and bet upon.