With good fortune we begin our study of Maseches Megillah, chapter one, mishnah one. This mishnah discusses the various dates on which the Megillah of Esther may be read in fulfillment of the mitzvah. The Megillah itself speaks of the fourteenth of Adar and the fifteenth of Adar, but our mishnah presents several alternative times.
The text of the mishnah:
"Megillah nikreis be'achad asar, bishneim asar, bishloshah asar, be'arba'ah asar, bachamishah asar, lo pachos v'lo yoser" - the Megillah is read, depending on the circumstances, on one of five days: the eleventh of Adar, the twelfth, the thirteenth, the fourteenth or the fifteenth. "Not less and not more" - not earlier than this and not later than this.
From here on, the mishnah spells out when and where the Megillah is read on each of these days.
Cities surrounded by a wall:
"Kerachin hamukafin chomah mimos Yehoshua bin Nun korin bachamishah asar" - cities that were surrounded by a wall from the days of Yehoshua bin Nun, when Israel entered the Land, read the Megillah on the fifteenth, even if they have no wall today.
This law is hinted at in the Megillah of Esther itself, even though there is no mention there of Yehoshua bin Nun. Seemingly it would have been more fitting to determine the matter according to the cities that were surrounded by a wall at the time of the Purim story, but two reasons are given for this:
Many of the cities in Eretz Yisrael were not surrounded by a wall at the time of the Purim story, since Israel was in exile. Therefore, in order to give honor to Eretz Yisrael, Chazal set the rule according to those cities that were surrounded by a wall in the days of Yehoshua, at the time of the conquest of the Land.
Yehoshua was the first to wage war against Amalek, and Haman came from the offspring of Amalek, and therefore the matter was fixed according to his days.
Villages and large towns:
After the law of the walled cities, the mishnah teaches that the villages, which are the small settlements, as well as the large towns that were not surrounded by a wall in the days of Yehoshua - "korin be'arba'ah asar" - read on the fourteenth, which is the regular day of Purim.
"Ela shehakefarim makdimin l'yom hakenisah" - the small villages, as we will see in the next mishnah, sometimes read the Megillah earlier, on the day of gathering: the preceding Monday or Thursday, when they were accustomed to come into the city. For this reason the reading may fall as early as the eleventh, the twelfth or the thirteenth.
In summary: in this mishnah we learned that the Megillah is read on one of five days - from the eleventh of Adar until the fifteenth of Adar, not less and not more. Cities surrounded by a wall from the days of Yehoshua bin Nun read on the fifteenth, and two explanations are given for this: the honor of Eretz Yisrael, and Yehoshua's war against Amalek, from whom Haman descended. The villages and the large towns read on the fourteenth, while the villages advance their reading to the day of gathering.
In the next mishnah we will examine the details of the law of the day of gathering and the way the days are divided.