Abu Hurairah reported,

The Messenger of Allah ﷺ said, "Horses are of three kinds. For one man they are a reward, for another they are a covering, and for a third they are a burden.As for the one for whom they are a reward, it is a man who tethers them for the sake of Allah and gives them a long rope to graze in a meadow or garden. Whatever they consume from that meadow or garden during the length of their rope counts as good deeds for him. If they were to break free from their rope and gallop a stretch or two, their tracks and droppings would be good deeds for him. If they were to pass by a river and drink from it without him intending to water them, that too would count as good deeds for him. So for him, they are a reward.As for the man who tethers them seeking independence and to refrain from begging, while not forgetting Allah's right concerning their necks and their backs, for him they are a covering.As for the man who tethers them out of pride, showing off, and hostility toward the people of Islam, for him they are a burden."The hadith continues.

عن أبي هريرة

أن رسول الله ﷺ قال: الخيل لرجل أجر ولرجل ستر وعلى رجل وزر، فأما الذي هي له أجر فرجل ربطها في سبيل الله فأطال لها في مرج أو روضة، فما أصابت في طيلها ذلك من المرج أو الروضة كان له حسنات، ولو أنها قطعت طيلها ذلك فاستنت شرفا أو شرفين كانت آثارها وأرواثها حسنات له، ولو أنها مرت بنهر فشربت منه، ولم يرد أن يسقي به، كان ذلك له حسنات فهي له أجر، ورجل ربطها تغنيا وتعففا ولم ينس حق الله في رقابها ولا في ظهورها فهي لذلك ستر، ورجل ربطها فخرا ورياء ونواء لأهل الإسلام فهي على ذلك وزر. الحديث.