The Torah informs the Jewish people in the Wilderness that each one must donate half a Shekel towards the building of the Mishkan. The Torah adds: הֶעָשִׁיר לֹא יַרְבֶּה וְהַדַּל לֹא יַמְעִיט, “The rich shall give no more and the poor give no less…” (Ex. 30,15) This presents an Halachic problem. Our Sages tell us: המבזבז – אל יבזבז יותר מחומש, “If a man wants to spend lavishly (on charity or a Mitzvah) he should not spend more than a fifth (of his wealth). (Ket. 50a)
In the case of the poor man, half a Shekel may represent more than a fifth of his possessions. How is he permitted to perform this Mitzvah?
Rabbi Soloveitchik posed this question and he answered by reading the remainder of the verse. The Torah states this money was to be given: לְכַפֵּר עַל נַפְשֹׁתֵיכֶם, “to atone for your souls.” In matters of the soul there are no limitations.
The Chafetz Chaim states that when it comes to studying Torah there is also no restrictions. We all know the story of Hillel who earned half a dinar a day and paid half of that to get into the House of Study. This is true for the study of Torah and is also an exception since it brings life and meaning to your soul.
We must be careful with our money so that we ourselves not have to resort to the help of others. However, in certain situations we must not withhold our help.