I heard Messenger of Allah (ﷺ) saying: "The case of a miserly man and a generous man who gives in charity is similar to that of two persons who are clad in armour from their breasts up to their collar bones. When the generous man gives in charity, his armour expands so much as to cover his fingertips and toes. When the miser intends to spend something the armour contracts and every ring of it sticks to the place where it is (sinks into his flesh). He tries to loosen it but it does not expand."

[Al-Bukhari and Muslim].