Megilla 5 How to Deal With A Well-Respected Rebel

Before beginning a new Mishna, we review some of the rabbis' thoughts about what to do when Purim falls on Shabbat.  The notion of "the proper time" is examined.  Shabbat is always observed and always at an understood, predetermined time. But what is "the proper time" to read the Megilla?  

Our new Mishna teaches us about large cities/villages, observance of the fast of the Ninth of Av/Hakhel, and eulogizing and fasting in villages that read the Megilla on the 14th of Adar/the 15th of Adar.

The Gemara explains that a city must have at least ten idlers, or congregants who are not paid to be at the service, to qualify as a city. The difference between city and village is important because it determines whether the Megilla reading might be postponed when Purim falls on Shabbat.  The rabbis note that we count years by months, and we count months by days.  Our calendar is predetermined and we cannot arbitrarily move celebrations without ample justification.  

At length, the rabbis discuss factors that might  allow the Megilla reading to be postponed.  Those factors include other guidelines, like the fact that we do not advance calamities, like the observance of the fast on the ninth of Av, but we might postpone them.  The also include practices like offerings on Festivals, placing hands on Festivals, and moving dates of other Festivals like Shavuot.

We are presented with the unusual actions of Rabbi Yehuda HaNasi.  He planted a sapling on Purim when labour was prohibited, he bathed on the seventeenth of Tammuz, and he tried to abolish the fast of the Ninth of Av even when the Sages disagreed with him.

Much of amud (b) is devoted to understanding these actions.  The rabbis might have characterized Rabbi Yehuda HaNavi as a man who has sinned, or they might have understood him as a man with different interpretations of Torah practice.  They did neither of these things.  Instead, they walk us through complicated possible explanations for his behaviour.  In each case, Rabbi Yehuda HaNavi was following halacha to the letter of the law.  This type of argument allows the rabbis to present their community as unified, even when they are fully engaged in argument.

Our daf ends with a question about walled cities.  We know that those living in cities that were walled from the time of Joshua celebrate Purim on the 15th of Adar, postponed from the 14th of Adar.  All others celebrate on the 14th of Adar.  But what if we aren't sure whether or not a city has four walls?  The Gemara uses Tiberius as one of its examples.  Tiberius is a walled city, but the fourth wall is the sea.  The sea blocks the city from intruders... but is the sea the same as a wall for the purposes of reading the Megilla on the 15th of Adar?