As we know, giving charity is considered to be one of the most important acts in Judaism. But is it possible to give too much?
Our obligation is to give between ten and twenty percent of our income in charity. A question is asked in Torah Lishmah, concerning someone who gives more than twenty percent of his income which, in addition to being more than his obligation, is beyond his means. Should he be prevented from giving this amount or, since charity is such a major obligation and foundation stone in Judaism, should he be permitted to give it?
The answer is that we see from the Gemara that not only are we permitted to prevent him, but it is actually necessary to do so, because he is giving more than his requirement and more than he is able to afford.
(See Torah Lishmah, Yoreh De'ah, She-elah Rosh Lamad Heth)