Most of this (rather long) section deals with whether work is prohibited on Purim.
Rabbi [Judah Hanasi] does three things here that later sages remember. First, he plants a sapling on Purim, even though planting is considered work. Second, he bathes on the Seventeenth of Tammuz which is a fast day. Third, he seems to try to abolish the fast of Tisha B’av altogether.
This last act seems to surprise R. Abba b. Zavda, who then offers a different version of what happened. The event occurred in a year on which Tisha B’av fell on Shabbat. The other sages wanted to observe it on Sunday (as we now do). But Rabbi wanted to get rid of it that year altogether. For better or for worse (depending on how much you like fasting in the middle of the summer) Rabbi did not win this one.
Elazar accepted R. Abba b. Zavda’s correction and remarked that two are better than one. Two rabbis are better at clarifying the tradition than one alone, who is more likely to err.
The Talmud now has a problem with the fact that Rabbi planted a sapling on Purim. R. Joseph offers a midrash based on the verse in the Megillah that says Purim is to be a day of “rejoicing, feasting and a good day.” From this verse he learns that one may not eulogize, fast or perform work on Purim. So how could Rabbi have planted a sapling?
The answer is that Rabbi lived in a place that celebrated Purim on the 14th. He planted the sapling on the 15th.
The problem is that Rabbi lived (at least most of his life) in Tiberias, which should celebrate Purim on the fifteenth, because it was (supposedly) walled during the times of Joshua.
The Talmud revises the previous statement—Rabbi planted on the fourteenth, and kept Purim the next day.
The problem is that Tiberias seems to have been of unknown status. Hezekiah, an amora, didn’t know whether Tiberias was walled at the time of Joshua. Therefore, he read the Megillah on both days.
The answer is that while Hezekiah wasn’t certain, Rabbi was. Somehow he knew that Tiberias was walled at the time of Joshua.
The problem with planting on the fourteenth of Adar is that there is a tradition in Megillat Ta’anit (the Scroll of Fasting—lists of days on which one is not to fast or mourn) that says there is no mourning on either the fourteenth or fifteenth. Rava points out that this is obvious—these dates are written in the Book of Esther itself. He therefore says that they are included in Megillat Ta’anit to teach that anything prohibited on one is also prohibited on the other. This would mean that if Rabbi couldn’t work on the fifteenth, he also couldn’t work on the fourteenth.
The Talmud resolves the difficulty by positing that Rava’s statement applies only to mourning and fasting—both are prohibited on the fourteenth and fifteenth. But the prohibition of work is for only one day.
The Talmud now cites a tradition of Rav, the amora, who cursed a man for planting flax on Purim. But this happened on the day that the man was supposed to be celebrating Purim. Rabbi, in contrast, planted the sapling the day before Purim.
Rabbah the son of Rava says that work may even be performed on Purim itself. He derives this from a discrepancy between Esther 8:17 and 9:22. The earlier verse refers to Purim as a “good day (Yom Tov)” implying that work is prohibited. However, the latter verse does not mention “Yom Tov.” Thus the Jews accepted that they are not allowed to mourn or fast on Purim, but the work prohibition they did not accept.
Rav cursed the man for planting because in Rav’s place the custom was not to work on Purim. If there is something that is actually permitted, but most people treat it as forbidden, one should not perform that act. In contrast, in Rabbi’s place they had no such custom to refrain from work on Purim. Therefore, for him it was permitted.
The Talmud offers another interpretation of Rabbi’s planting. Generally work was not performed in Rabbi’s place on Purim, even if it was not strictly prohibited. Rabbi was not planting a regular sapling—he was planting a “festive sapling.”
To understand what this sapling is the Talmud cites a mishnah from Ta’anit which says that if the Jews have fasted and rain still did not come, they lessen most of their activities. A baraita explains that they do not build “festive building” or plant “festive planting.” The former refers to building a house for one’s son on the occasion of the son’s wedding. The latter refers to planting an abarnaki. Rashi explains that this is a tree trained over a lattice structure whose sole intent is to provide shade. It is not meant for fruit or wood, just the luxury of shade. Such a tree may not be planted if it has not rained for a long time, because people should be mourning, and probably not planting luxury trees. But Rabbi is allowed to plant such a tree on Purim, because it’s less of an act of work and more an act of rejoicing.
Today’s section returns to the issue of when the Megillah is read in Tiberias, on the fourteenth or fifteenth. In other words, was Tiberias walled at the time of Joshua?
How could Hezekiah have been doubtful as to whether Tiberias was a walled city at the time of Joshua? There is a tradition that the city of Rakat mentioned in Joshua 19 is Tiberias. It was certainly walled at the time of Joshua.
The answer is that it was walled on only three sides. The fourth side was the Sea of Galilee.
But there should be no doubt that Tiberias does not count as a walled city for there is a midrash that specifically says that Tiberias’s sea does not count as its wall.
The topic of this midrash is redeeming houses which were sold in a walled city. I suggest you look up Leviticus 25 for more information concerning the topic.
The Talmud now explains that when it comes to redeeming a house in a walled city, an actual wall is required for it to be considered a wall city. Tiberias is not a walled city because it is not surrounded on all four sides by walls. But Megillat Esther does not use the word “walled city.” Instead it uses the term “perazi” which I have translated as “villages” but is less explicit. Hezekiah wasn’t sure whether the difference between villages and walled towns is that walled towns are totally enclosed. If so, Tiberias is exposed on one side, because there is no wall. Alternatively, the difference is protection. Tiberias is protected, because the one open side is blocked by the sea.
This is why Hezekiah was in doubt about Tiberias. He knew it was walled on three sides from the time of Joshua. He just didn’t know whether cities walled on three sides were considered walled cities with regard to reading the Megillah.
According to the first version of this tradition, R. Assi treated Huzal, a city in Babylonia, as a city whose status was doubtful. Therefore he read on both days.
According to the second version, Huzal was walled at the time of Joshua and therefore reads on the fifteenth.
The big problem is: Where is Huzal? According to a different passage in the Talmud, Huzal is in Babylonia. This would demonstrate that the rule of walled cities reading on the fifteenth applies to Babylonia. However, according the second tradition here, it seems that Huzal is in Israel, for it is called “Huzal of [the tribe of] Benjamin.” There are many variants readings of this, both here and in Ketubot. The bottom line is that it is not all that clear where Huzal is. The issue was discussed by many medieval authorities who questioned whether the difference between walled cities and villages is relevant outside of Israel.