Musnad Ahmad 396:1

Mu'awiyah ibn 'Amr narrated to us, he said: Za'idah narrated to us, he said: Ar-Rukayn ibn ar-Rabi' ibn 'Amilah narrated to us, from Abu 'Amr ash-Shaybani, from a man of the Ansar, from the Prophet, who said: "Horses are of three types: A horse that a man ties in the way of Allah, the Mighty and Majestic; its price is a reward, its riding is a reward, its lending is a reward, and its fodder is a reward. A horse that a man uses for gambling and betting; its price is a burden of sin, and its fodder is a burden of sin. And a horse for one's own sufficiency; it may be a protection against poverty, if Allah the Exalted wills."