Sahih Muslim Book 5, Hadith Number 2229.

Chapter : Proof of reward for the giver of charity even if it goes into the hands of and undeserving person.

Abu Haraira reported Allah’s Messenger (may peace be upon him) as-saying:. The similitude of a miserly man and the giver of charity is that of two persons with coats-of-mail over them; when the giver of charity intends to give charity, it expands over him (to much so) that the footprints are also obliterated. And when the miserly man intends to give charity, it contracts over him, and his hands are tied up to his collar bone, and every ring is fixed up to another. He (the narrator) said: I heard the Messenger of Allah (may peace be upon him) as saying: He would try to expand it, but he would not be able to do so.