Musnad Ahmad 30:1856

'Affan narrated to us, Wahib ibn Khalid al-Basri narrated to us, he said: Suhayl narrated to us, from his father, from Abu Hurayrah, from the Prophet (peace and blessings of Allah be upon him), who said: "There is no owner of treasure who does not pay the Zakat of his wealth, but he will be brought on the Day of Resurrection along with his treasure, and it will be heated into plates in the fire of Hell, and his forehead, his side, and his back will be branded with them, until Allah judges between His servants on a day the measure of which is fifty thousand years of what you count. Then he will see his path, either to Paradise or to the Fire. And there is no owner of camels who does not pay their Zakat, but he will be brought on the Day of Resurrection along with his camels in the most abundant state they ever were. He will be thrown down for them on a flat, level plain; every time the last of them passes, the first of them returns to him, until Allah judges between His servants on a day the measure of which is fifty thousand years of what you count. Then he will see his path, either to Paradise or to the Fire. And there is no owner of sheep who does not pay their Zakat, but he will be brought along with his sheep on the Day of Resurrection in the most abundant state they ever were. He will be thrown down for them on a flat, level plain; they will trample him with their hooves and gore him with their horns. Every time the last of them passes, the first of them returns to him, until Allah judges between His servants on a day the measure of which is fifty thousand years of what you count. Then he will see his path, either to Paradise or to the Fire." It was said: "O Messenger of Allah, what about horses?" He said: "Good is tied to the forelocks of horses until the Day of Resurrection. Horses are of three types: they are a reward for a man, they are a covering for a man, and they are a burden upon a man. As for the one for whom they are a reward, it is the man who takes them and keeps them for the sake of Allah; whatever they consume in their bellies is a reward. Even if they run across a hill or two, he will have a reward for every step they take. And if they come across a river and he lets them drink from it, he will have a reward for every drop they consume in their bellies," until he mentioned the reward for their dung and their urine. "As for the one for whom they are a covering, it is a man who takes them for the sake of chastity, adornment, and nobility, and he does not forget their right regarding their backs and their bellies, in their hardship and their ease. As for the one upon whom they are a burden, it is a man who takes them out of arrogance, pride, showing off to people, and vanity toward them." It was said: "O Messenger of Allah, what about donkeys?" He said: "Nothing has been revealed to me regarding them except this comprehensive, unique 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} [Az-Zalzalah: 7-8]."