Harav Yisrael Friedman related:
My father, Rav Yitzchak Friedman, the son of the Pashkaner Rebbe, who was very friendly with Reb Shmuel, once traveled to the Imrei Chaim of Vizhnitz. My father asked the Rebbe to instruct Reb Shmuel to reduce the sums of money he distributed to tzedakah.
“Reb Shmuel gives too much tzedakah — more than a fifth — and Chazal say that one must not give more than a fifth. As a friend of his, I am really afraid for Reb Shmuel’s money,” my father explained to the Rebbe.
The Rebbe smiled and wisely answered: “Harav Levi Yitzchak of Berditchev asks about the nusach of the brachah we make on Yom Kippur, ‘Melech mochel vesolei’ach la’avonoseinu.’ How can we say so confidently that Hashem forgives us if we can’t be sure, since Yom Kippur only atones for those who repent?
“Replied the Berditchever, ‘We make the brachah with the Name of Hashem, and Hashem does not want us to utter His Name in vain, and therefore He forgives and has mercy on us above and beyond what is warranted.’
“Reb Shmuel does the same thing,” the Rebbe explained. “First, he gives a sum to tzedakah. Then, so that he does not transgress what Chazal say — that one should not give more than a fifth to tzedakah — Hashem increases his fortune based on the amount of tzedakah he has given, so that it should increase to be five times as much as the donations!”
It should be noted that when his family asked Reb Shmuel why he gave more than a fifth, he would reply wittily, “Chazal said ‘He who wastes should not waste more than a fifth,’ meaning that only someone who feels that tzedakah is a waste is not allowed to give more. But someone who knows that tzedakah is not a waste, but rather a true investment, is permitted to invest more than a fifth.”