All income that a person receives, even as a gift or an
inheritance, should be tithed after deducting all expenses, such as taxes,
traveling expenses, salaries paid to workers, damage caused to merchandise
by theft, fire, etc., when the loss is not covered by insurance. (Money
received from an insurance company in compensation for damaged merchandise
need not be tithed unless it is in excess of the value of the merchandise.)
Nevertheless, the value of one’s own labor may not be deducted from the
sum to be tithed.
When a person with two businesses profits from one and
suffers a loss from the other, if he has already calculated the tithe from
his profitable business, he may not deduct his loss from the sum to be
tithed. But if he did not yet calculate the tithe, and if he calculates the
tithe only at the end of the year or other fixed period of time, he is
permitted to deduct his loss from the sum which he tithes.
A woman who has an independent income is also required to
tithe. But if she gives to her husband money she earned and tithed before
she was married, he is not required to tithe it.
Wedding gifts, money that is found, a debt which had been
written off as uncollectable, money that seemed to be irretrievably lost and
was then recovered—all of these should be tithed.
Money that is borrowed need not tithed. Income acquired
to pay a debt should be tithed.
If a sum of money that was set aside as a tithe is stolen
or lost under circumstances where the owner was not negligent, he may or may
not be required to replace it. If he said, when separating the tithe, “This
money is tithe money,” he is not required to replace it. But if he said
that he was obligated to provide tithe money equal to the sum of money which
he had set aside, he is required to replace it unless he had already
declared that he was not responsible to replace if it were lost or stolen.
If a person uses money set aside as a tithe for his own purposes, he is
required to replace it.
It is permitted to give charity and to deduct it from a
tithe that will be taken later. If a person gives charity in excess of his
tithe, he is permitted to reduce the tithe he takes for the following period
by the amount in excess of his previous tithe.
Unless otherwise stipulated, tithe money should be
distributed immediately and, for that reason, should not be invested in
business even if all the profits will be given to the poor.
If stipulated beforehand, tithe money may be invested in business or used
to buy a lottery ticket. Do the profits belong to the owner of the tithe or to
the poor? The poskim disagree. But it seems clear that if a person lends tithe
money for interest with a commitment to replace it if it is lost, he has a
right to any profits that accrue.