Laws of the Megillah
23. A city which was surrounded by a wall at the time of Joshua ben Nun's
("son of Nun") conquest of the Land of Israel (1), should read the
Megillah on the fifteenth of Adar (2) (This is not a very common
circumstance in our provinces) (3).
(1) Joshua led the Jews into the Land of Israel in 1272 BCE.
(2) The Megillas Esther (9:19) states: "Therefore, the Jews...living in
UNWALLED cities celebrate the 14th day of the month of Adar," however, it
doesn't specify when those in walled cities should celebrate Purim. The
Talmud (Megillah 2b) concludes that walled cities should celebrate on the
15th of Adar, just like Shushan, a walled city, did at the time of Purim
(the battle against the enemies of the Jews in Shushan lasted one day
longer than the war in other cities, and thus the victory was celebrated
there on the 15th rather than the 14th - see Esther 9:15).
Why should the status of a city be based on whether it had a wall at the
time of Joshua's conquest rather than whether it had a wall at the time of
the miracle of Purim? There are two main reasons given:
a) Had it been based on whether a wall existed at the time of Purim, the
great cities of the land of Israel would have to be classified as unwalled
cities, because their walls lay in ruins at the time of Purim, due to the
Babylonian conquest. Therefore, by setting the criterion back to the time
of Joshua, the cities of the land of Israel received the honor of reading
with the walled cities (Jerusalem Talmud).
b) Since it was Joshua who led the first battle against Amalek when the
Jews left Egypt (Exodus 17:8-16), the sages felt it appropriate to
associate his name with the celebration of the downfall of Amalek at the
time of Purim (Haman was an Amalekite).
(3) The Kitzur Shulchan Aruch is referring to the Jewish communities in
Europe in the late 19th Century.