It is narrated from Sayyiduna Abu Huraira (may Allah be pleased with him) that the Messenger of Allah (peace and blessings of Allah be upon him) said: "For one person, horses are a source of reward, for another they are a means of livelihood, and for another they are a source of sin. Reward is for the one who keeps them for jihad, then lets their rope loose in a field or pasture, so however far they graze because of that rope, good deeds are written for him. And if they reach a river and drink water, and the owner did not intend to give them water, even then good deeds are written for him. And they are a means of livelihood for the one who keeps them for trade and pays their zakat. And they are a source of sin for the one who keeps them for pride, showing off, and enmity towards Muslims." And the Messenger of Allah (peace and blessings of Allah be upon him) was asked about donkeys. He said: "Nothing has been revealed to me regarding this matter, except this verse which alone encompasses all good deeds: «﴿فَمَنْ يَعْمَلْ مِثْقَالَ ذَرَّةٍ خَيْرًا يَرَهُ وَمَنْ يَعْمَلْ مِثْقَالَ ذَرَّةٍ شَرًّا يَرَهُ﴾ [الزلزلة: 8] » ."