Mukhtasar Bukhari

Narrated Abu Huraira (may Allah be pleased with him): The Prophet (peace and blessings of Allah be upon him) said: "Whoever keeps a horse for fighting in the way of Allah, solely out of faith in Allah and believing in His promises, then surely its food, drink, dung, and urine—in short, everything related to it—will become reward for him and will be weighed in his scale of deeds on the Day of Resurrection."