Among the stories told by the Gemara about miraculous occurrences that happened to righteous individuals is one related about Elazar ish Birta, from whom charity collectors always kept their distance. The reason that they would hide from him whenever they saw him was because he would give away every last penny that he had.
The Gemara relates that he was heading for the marketplace to purchase things in preparation for his daughter’s wedding. On his way, he noticed a number of people who were collecting charity. Although they tried to avoid him, he chased them down and demanded to know what cause they were collecting for at this time. They reluctantly told him that they were collecting money for a wedding. Two orphans were getting married, and they had to rely on charity to put together the wedding. Elazar ish Birta immediately declared that the orphans’ need came before his own daughter’s needs and gave them everything he had.
Before returning home, he realized that there was a single zuz remaining, and he purchased a small amount of wheat. He went home and stored the wheat in his granary. When asked what he had purchased for the wedding, he replied that he had put it in the granary. His wife went to check and discovered that, miraculously, the granary was so full that she could not even open the door. When she ran to tell her husband what happened, he told her that they could only benefit from it like any poor person, since he did not intend to derive benefit from a miracle.
One of the major issues dealt with in the context of this story is that the Sages had ruled (as one of takkanot Usha) that a person cannot donate more than one-fifth (20%) of his possessions to charity. The Rambam, in his commentary on the Mishna, argues that one-fifth is appropriate for someone who wants to fulfill the mitzva, but it is not forbidden to donate more; rather, it is a midat hasidut – a pious attribute – to do so. It is also possible that this story took place prior to the establishment of takkanat Usha.