The idea that donors benefit from tzedakah as much or more than the poor is a common theme in Jewish tradition. Whereas the poor recieve money or other material assistance, the donor receives the merit of sharing in the Almighty’s work. The Baal Haturim makes the point in a beautiful commentary on the word v’ntnu (and you will give), a palindrome in Hebrew which appears in Exodus, 30:12.
V’ntnu if it is written backwards, it is also v’ntnu to tell you that whatever a person gives to tzedakah will return to him and he will not lack anything because of it.
The Midrash makes the same point, this time based on a verse in the Book of Ruth:
R. Yehoshua taught: More than the householder does for the poor, the poor do for the householder. As Ruth says to Naomi [when Naomi asked where she had gleaned so much] (Ruth 2:19) “The name of the man for whom I did things today is Boaz.” Note it refers to what “I did for him.” In other words I did for him many things and much goodness in exchange for the slice he gave me. Vayikra Rabba 34:8.