The Rosh writes (Orchas Chaim 5:80), “Do not fail to
bring maaser to the collection center for the poor, for “a gift in
secret pacifies anger…” (Mishlei 21:14)
Regarding the obligation to tithe income from profits there
are several opinions. Some say it is from the Torah, some say it is rabbinical
and others hold that it has the force of a customary way to fulfill a mitzvah,
and such customs may not be violated unless there is a great need. Even
according to the opinion that it is a custom, once a person conducts himself
as custom requires, it is as though he has taken a vow to keep the custom.
With that, the obligation to tithe his income is reinforced by the Torah
obligation to keep vows. For that reason, it is appropriate that, when tithing
for the first time, a person should say that, in doing so, he is not making a
vow. Tosphos, in parshas Vayeitzei, cite a midrash that Yaakov Avinu is the
one who established that income should be tithed: “And all that you give
me I will tithe to You.” (Bereishis 28:22)
Even though, in all mitzvos, it is forbidden to test G-d,
as it is written, “Do not test the L-rd your G-d.” (Devarim. 6:16), it is
permitted to test G-d by tithing income: Bring all the tithes into the
storehouse, so that there may be food in my house, and put me to the test with
that, says the L-rd of hosts, if I will not open for you the windows of
heaven, and pour out for you immeasurable blessing. (Malachi 3:10) Most poskim
hold that the permission to test G-d applies to tithing of money and giving
charity as well as tithing of grains. Nevertheless, the test only applies to
the acquisition of wealth. To test G-d for the sake of any other benefit, such
as the recovery of a child from illness, is forbidden. The promise of wealth
only applies when the tithe is made on the condition of receiving wealth and
with absolute faith that G-d will keep his promise. Nevertheless, the Matteh
Ephraim writes that if a person sees that he is not becoming wealthy, he
should know that G-d knows that that is what is best for him. [In addition, it
seems to me that that there is no promise that a person who tithes his income
will become wealthy right away. It might take a long time. This explains why
the poor are exempt from tithing their income, even though it carries a
promise of wealth and would not, it seems, make them poorer: they need the
money to support themselves now, and the promise of wealth may not be
fulfilled for a long time.]
The obligation to tithe income derives from the mitzvah of
tzedakah, so when a person tithes his income, he fulfills the mitzvah of
tzedakah. How much tzedakah should a person give? If he is wealthy enough,
should give as much as the poor require, even if it means giving away even
more than a fifth of his income. Otherwise, the mitzvah is fulfilled in the
best way by giving one fifth of one’s income. One-tenth is also acceptable.
Less than that is considered stingy. A person should not ordinarily give more
than one-fifth of his income lest he, himself, become impoverished.
Nevertheless, the Chafetz Chaim in his sefer Ahavas Chesed lists
the circumstances in which he may give more:
When it will save a life.
When there are poor people in his community.
When a person is so wealthy that there is no danger of his
becoming impoverished by giving charity.
If he has a source of regular and reliable income.
To support Torah study. Because he has a portion in it, he
is considered like a partner.
A person who, in any case, spends a great deal of money on