Tosfos (Bava Kamma 9b) writes that it is evident from our Gemora that a person is not obligated to give up all of his possessions in order to fulfill a mitzvah, and even for a mitzvah that will pass in time, such as an esrog. It is further evident from the conclusion of the Gemora that one is not even obligated to give up a third of his possessions in order to fulfill a mitzvah. And furthermore, it is said regarding charity: One who gives liberally to charity should not give more than a fifth of his money, for then, he will be forced to beg for support himself.
The Rosh writes that this halacha applies by all mitzvos; one should not spend more than a fifth of his wealth on any specific mitzva, such as esrog or lulav. The Rambam and Rema seem to rule accordingly.
Why not Spend?
The Rishonim ask: Why would someone be exempt from performing a mitzvah just because it costs more than a fifth of his wealth? The Ra’avad answers that this is similar to halacha that one should make his Shabbos like an ordinary weekday, and not be forced to be supported from charity. This is because poverty is regarded as death, and one is not obligated to give up his life for an ordinary mitzvah.
The Biur Halachah writes (in his explanation of an opinion from the Beis Yosef) that not all mitzvos are compared to charity, for charity is a mitzvah that will not pass in time, and even if the poor people are before him, they can be supported by another person. That is why one would not be obligated to spend more than a tenth of his possessions. However, with respect to a mitzvah that will pass in time, it is possible that there would be an obligation to spend more than a tenth.
Reb Yaakov Emden asks: Why isn’t there an obligation to spend more for a positive commandment? Did we not learn regarding one who does not want to fulfill a positive commandment – we beat him until his soul departs him? Do we treat his money stricter than his life?
The Maharitz Chayus answers that we only beat him until his soul departs him when he is rebelling against the fulfillment of mitzvos; otherwise, we do not beat him, and he would not be required to spend all his money for it.
Lo Sa’aseh is Different
The Ra’avad adds that this halacha applies only to a positive commandment; however, one would be required to spend his entire wealth in order not to transgress a negative precept.
Must he Spend a Fifth?
The Gemora (Kesuvos 50a) states that one should not spend more than a fifth of his wealth to fulfill a mitzvah; is one halachically required to spend up to that amount, or is it only regarded as a mitzvah?
The Beis Yosef (Y”D; 249) writes that it is considered a mitzvah in the preferable manner if one spends up to a fifth of his wealth in order to perform a mitzvah. The Beis Yosef adds that although one can imply from the Gemora that it is not even a mitzvah to spend that amount because the Gemora states: One who spends liberally should not give more than a fifth of his wealth; however, even less than that would be regarded as spending liberally, and there would be no mitzvah whatsoever to spend that amount. Nevertheless, there is a Yerushalmi in Pe’ah that seems to indicate that there is a mitzvah to spend up to one-fifth of his wealth for a mitzvah.
In the sefer Ahavas Chesed, the Chafetz Chaim cites a Rambam in his explanation to the Mishnayos, who writes that there is a halachic obligation to spend up to one-fifth of one’s wealth for charity. He asks form our Gemora, which would seem to indicate that there is no such obligation. He answers that our Gemora is discussing a case where the poor people are not present and someone is searching to find them in order to give them charity. In such a situation, there is not even a mitzvah to give up to one-fifth. However, the Yerushalmi and the Rambam are speaking about a case where the poor person is in front of you; then, there would be a halachic obligation to give up to one-fifth.
Spending More than a Fifth
What if one wants to spend more than a fifth? Is he allowed to? It is evident from the Rambam in his explanation to the Mishnayos that it is regarded as virtuous (midas chassidus) for one to spend more than a fifth. However, it can be inferred from the Rambam in halachos that one should not spend more than a fifth of his wealth on a mitzvah.
The Chafetz Chaim reconciles the two rulings of the Rambam in the same manner as before. If the poor person is present, it would be regarded as midas chassidus to spend more than a fifth, and that is what the Rambam in his explanation to the Mishnayos is discussing. However, when the poor people are not present and one is chasing after them, he should not spend more than a fifth.
The Shitah Mekubetzes writes that one is permitted to spend more than a fifth of his wealth if it is to support the studying of Torah. The Ahavas Chesed explains the reasoning for this. One who supports another fellow to learn Torah is creating a partnership with him; the supporter receives a reward together with the one who is learning the Torah. One is permitted to purchase this reward for himself even if it will cost him more than a fifth.
Reb Moshe Feinstein (Igros Moshe (Y”D, 4:37) rules that this is correct only if the supporter specifically negotiates with the one studying Torah to create a partnership of Yissochar and Zevulun. However, if the provider is just donating money to support Torah, he is not permitted to give more than a fifth.
The Ibn Ezra in Mishlei (4:7) writes that one is permitted to spend more than a fifth of his wealth in order to study Torah himself. The Chafetz Chaim in Likutei Halachos (Yoma 12a) also rules like that. However, the Netziv in the Shiltos states that this is a matter of dispute between two Amoraim. The Gemora in Eruvin cites the verse that Torah is not in the Heavens. Rav Avdimi says: If it would be in the heavens, one would be obligated to go there and learn. It is evident that one would be forced to spend more than a fifth of his wealth to study Torah, for otherwise, he could claim that it costs too much to travel to the Heaven. However, Rava disagrees regarding the interpretation of that verse, and according to him, one would not be allowed to spend more than a fifth in order to study Torah.
The Rema (Y”D, 249:1) seems to hold that one can give away more than one-fifth of his wealth to charity right before he dies. It is brought in the name of Rabbeinu Yonah that even then, he should not.
It is written in Ahavas Chesed that one who is a free-spender in regards to himself and his family, i.e., he splurges on expensive clothing, builds for himself a fancy mansion and generally leads a luxurious lifestyle; it is permitted for him to give to charity more than a fifth of his wealth.
Some say that if one finds himself in dire straits, he is permitted to spend more than a fifth with the intention that it should be on account of this deed that he will merit a salvation. It is brought in the name of the Bnei Yissoschar that one who requires atonement on a specific sin is also permitted to give away more than a fifth.