Sahih Muslim, Hadith 1021b

Abu Haraira reported that the Messenger of Allah (ﷺ) gave similitudes of a miserly man and the giver of charity as two persons who have two coats-of-mail over them with their hands pressed closely to their breasts and their collar bones. Whenever the giver of charity gives charity it (the coat-of mail) expands so much as to cover his finger tips and obliterate his foot prints. And whenever the miserly person intends to give charity (the coat-of-mail) contracts and every ring grips the place where it is. He (Abu Huraira) said: