chesedname – Most wealthy people are not satisfied with what they have and have never said that they have enough.
So the promise that you reference is allegorical: If you give Tzedaka, you will get back more than you give. So the more you give, the more you get since Hashem sees that you are a good repository for His money to be dispensed to the poor. We are in essence Hashem bank tellers; He deposits with us and the poor withdraw.