The Messenger of Allah ﷺ said, "Horses are a source of reward for one man, a shield for another, and a burden upon a third.As for the one for whom they are a reward, it is a man who tethers them for the sake of Allah in a meadow or pasture. Whatever they consume during the time they are tethered there in the meadow or pasture is recorded as good deeds for him. If they were to break loose from their tether and gallop a stretch or two, their tracks" — and in the narration of Harith, "and their droppings" — "would be good deeds for him. If they passed by a river and drank from it without him intending to water them, that too would be good deeds for him. So for him they are a reward.As for the man who tethers them seeking self-sufficiency and to avoid begging, while not forgetting the right of Allah regarding their necks and their backs, for him they are a shield.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 Prophet ﷺ was asked about donkeys, and he replied, "Nothing has been revealed to me concerning them except this comprehensive, singular verse, 'So whoever does an atom's weight of good will see it, and whoever does an atom's weight of evil will see it'" [Zalzalah 99:7–8].
أخبرنا محمد بن سلمة والحارث بن مسكين قراءة عليه وأنا أسمع واللفظ له عن ابن القاسم قال حدثني مالك عن زيد بن أسلم عن أبي صالح السمان
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 في المرج أو الروضة كان له حسنات ولو أنها قطعت طيلها ذلك فاستنت شرفا أو شرفين كانت آثارها وفي حديث الحارث وأرواثها حسنات له ولو أنها مرت بنهر فشربت منه ولم يرد أن تسقى كان ذلك حسنات فهي له أجر ورجل ربطها تغنيا وتعففا ولم ينس حق الله عز وجل في رقابها ولا ظهورها فهي لذلك ستر ورجل ربطها فخرا ورياء ونواء لأهل الإسلام فهي على ذلك وزر وسئل النبي ﷺ عن الحمير فقال لم ينزل علي فيها شيء إلا هذه الآية الجامعة الفاذة {فمن يعمل مثقال ذرة خيرا يره ومن يعمل مثقال ذرة شرا يره}
Bukhari narrated it in the chapters on Musaqah, in the chapter "People Drinking and Watering Animals from Rivers," hadith no. 2371, from the hadith of Malik. Muslim narrated it in the chapters on Zakat, in the chapter "The Sin of Withholding Zakat," hadith no. 24/987, from the hadith of Zayd, through him. It is also found in Al-Kubra, hadith no. 4403.