When the fifteenth of Adar falls on Shabbat, Purim is
celebrated over a three-day period in the "walled"
cities [Jerusalem and Shushan]. Other cities fulfill all of the
obligations of Purim on Friday, the fourteenth. Those who are
obligated to celebrate Purim on the fifteenth, however, divide
the obligations over the period between the fourteenth and
sixteenth. How is this done?
The mitzvot of reading the Megillah and giving gifts to the
poor are fulfilled on the fourteenth, as in the other cities. On
Shabbat, the fifteenth, a second Torah scroll is taken from the
Sanctuary and the portion from the parsha of Beshallach that
tells of the war with Amalek is read. The Al ha-Nissim prayer is
added to the Amidah and the Grace after Meals. On Sunday,
the sixteenth, the festive meal is held and gifts of food are
sent to friends.
Why was it decided to fulfill the mitzvot of Purim in this
Although the Megillah should be read in the "walled
cities" on the fifteenth, the Sages prohibited the reading
of the Megillah on Shabbat, lest the Megillah scroll be
inadvertently carried in the public domain by people seeking
someone capable of reading it for them,a violation of the laws
of Shabboat. When then was the reading not delayed until Sunday,
the sixteenth? The Sages deduced from specific verses of the
Megillah that when the reading cannot be done at its proper
time, it should be read earlier than required rather than later.
[This is in contradiction to other Rabbinic obligations, e.g.,
the fast of Tishah b'Av, which are fulfilled later, if the time
for their fulfillment falls on Shabbat. The verse in the
Megillah states: “And these days of Purim shall not pass”
(Esther 9:27) ? that is, we are not permitted to allow the days
of Purim, the fourteenth and fifteenth of Adar, to pass without
our having observed the mitzvah, but we are permitted to do so
earlier than required.
The mitzvah of eating the festive Purim meal is delayed until
the sixteenth [even though it could theoretically be fulfilled
on Shabbat, the fifteenth] because of our tradition that we do
not mix one celebration [in this case Shabbat] with another [in
this case the Purim meal].
The giving of gifts to the poor and the exchange of
mishlo'ach manot between friends cannot be fulfilled on Shabbat,
again because we fear that doing so might lead one to
inadvertently carry in the public domain. The former obligation
is moved to the fourteenth, so that the poor might enjoy their
gifts as early as possible. The latter obligation is delayed
until the sixteenth since the verse in the Megillah, from which
we deduce that we do not allow the days of Purim to pass, does
not refer to the mitzvah of exchanging gifts. Additionally, by
delaying its fulfillment until the sixteenth of Adar, we
establish a noticeable difference between the celebration of
Purim in the walled cities and in other cities.
Although the mitzvah of reading the Megillah can be fulfilled
without a minyan, when this mitzvah is fulfilled earlier than
required [i.e., when the fifteenth falls on Shabbat and the
residents of the walled cities move the reading to the
fourteenth] it is customary to read only in the presence of a
minyan. This also applies to the reading of the Megillah for
women; i.e., it should be read in the presence of ten women.
Although the sending of mishlo'ach manot is delayed until the
sixteenth, it is nevertheless customary for the residents of
walled cities to send a few to friends on the fourteenth. It is
also traditional to make the Shabbat meal more elaborate than
usual, in honor of Purim. It is customary for the residents of
the walled cities to dress in festive clothing en the sixteenth
to indicate that they are celebrating Purim. As noted, the A1
ha-Nissim prayer is recited on Shabbat, the fifteenth, and is
not recited on the sixteenth, neither in Shemoneh Esreh nor in
the Grace after Meals.