I heard a vort on this once….
When a person keeps their hands closed, (meaning refrains from giving tzedakah, chesed, etc.) it’s hard for them to see the individual needs of each person (i.e all the fingers the same length),,,but when he opens his hand, (opens his heart to giving) each finger is a different lenghth then he is able to see each person in need and what type of chesed is required for that individual person.