Umayyah ibn Bistam narrated to me: Yazid — meaning Ibn Zuray' — narrated to us: Rawh — and he is Ibn al-Qasim — narrated to us, from Zayd ibn Aslam, from his father, from 'Umar, that he had given a horse for the sake of Allah, then found it with its owner who had neglected it, and the man was of little wealth. So 'Umar wanted to buy it back, and he came to the Messenger of Allah, peace and blessings be upon him, and mentioned that to him. He said: "Do not buy it, even if you are given it for a dirham, for the likeness of one who returns to his charity is like the dog that returns to its vomit."