Mukhtasar Muslim

Amir al-Mu'minin Sayyiduna Umar bin Khattab (may Allah be pleased with him) says: I gave a fine horse in the way of Allah, and the one to whom I gave it ruined it. I thought that now he would sell it for a low price. I asked the Messenger of Allah (peace and blessings of Allah be upon him), and he said: Do not buy it, and do not take back your charity. For the one who takes back his charity is like a dog who vomits and then eats it again.