On this daf, we find the times when we read the megillah.
The Alter of Kelm writes, “A discerning person understands that the reason given for a particular mitzvah or to avoid an aveirah is not the entire reason behind it. For example, the verse states that we eat matzah since our ancestors did not have time to let their bread rise. This is not enough of a reason for the many stringencies and decrees of Pesach. Why would our sages prohibit even the slightest amount of chometz if this were the only reason? The entire Torah and the decrees of the sages are based on deeper reasons.”
The Mekor Chaim writes, “The Zohar reveals that what we do below parallels spiritual realities above. Every decree was made not only for the simple reason, but for a deeper one that was applicable at the time, and most often beyond when the simple reason of the decree does not apply.
“For example, we read the MegiLlah on the fourteenth of Adar everywhere except places that have a wall from the time of Yehoshua bin Nun. The Yerushalmi explains that this was to honor Eretz Yisroael. Although its cities were largely destroyed at that time, any city with a wall from the times of Yehoshua reads on the fifteenth. The only exception to this is Shushan. Although it was not walled-in from the days of Yehoshua bin Nun, we still read there on the fifteenth, since the miracle took place there.
“Nevertheless, although that is certainly true, there are also deeper reasons for this as well. The deeper works reveal that there is a bigger illumination on Shushan Purim in Yerushalayim than the fourteenth of Adar everywhere else.
“Purim is the time when one receives the ability to hold strong despite this seemingly endless exile. On this day, we accept the Torah anew from a deep love and desire for Hashem. On this day, those who are most distant are afforded special protection and love. We all should appreciate this and work to reciprocate. On Shushan Purim, in a city walled from the days of Yehoshua bin Nun, we receive an even greater portion of the above.”
Is it any wonder that the sages did not discuss the simple reason for their decreeswhen there is so much more imbued in them? (Kisvei HaSaba V’talmidov, Part I-II, p. 239; Mekor Chaim, Hilchos Purim).