A few quotes from the Rabbi on 'Tzedakah and Healing'
in which he teaches that opening one's hand to the poor opens Heaven's treasury to bless his actions
From my heart's musings, I say: The very act of giving charity is, in itself, a blessing. There is no blessing greater than a person who has been granted the privilege of wealth by the Creator and who can help the poor and needy, share his bread with the hungry, and give of his money to revive unfortunate souls. He enacts "and you shall be a blessing". By opening your hand to the poor and needy, you are the one influencing and opening Heaven's treasury to bless all your actions, therein is the blessing.
Eshed Hanechlim, Part 3, p. 266, Raphael Ben Haim Hacohen Press, Jerusalem, 2009