- The Ran notes that there is a concept (Bamidbar 15:16) that there is one Torah and one law for all Jews. In other words, there should ordinarily be only one day for all Jews to celebrate together. For this reason, Mendel Weinbach notes, usually, according to Halacha (Mishna Berura 688:12), where one spends Purim determines when one will celebrate it. For example, a Jew visiting a walled city temporarily nevertheless celebrates it there for purposes of achdus (“unity”).
- R’ Betzalel haKohen of Vilna, however, writes that this distinction is meant to stress that Purim is a d’rabbanan (“rabbinic”) holiday, since the Torah’s (Devarim 13:1) prohibition to add to the given mitzvos only applies to d’oraisa (“Scriptural”) laws.
- A story is told of a visitor from Bnei Brak in the home of R’ Shlomo Bloch in Yerushalayim. R’ Bloch invited him to drink at his Purim feast (on Shushan Purim), but since he had already drunk the previous day, the visitor argued that he had already fulfilled the mitzva of drinking on Purim. R’ Bloch retorted, “You may have fulfilled Purim, but you can still fulfill the mitzva of feeling another Jew’s joy.”
- The Chasam Sofer gives another reason to have two days of Purim – to avoid bitul Torah. Since the Mishna (Avos 1:2) teaches that Torah is one of the three foundations upon which the world stands, if there were (chas v’Shalom) one moment when nobody was learning Torah, the world would cease to exist immediately. With the advent of Shushan Purim, while one group is drinking and celebrating, the other group can uphold the world by learning.
- The Maamar Mordechai writes that Esther mentions the Jews of Shushan specifically because they had been under the threat of annihilation the earliest, and had knowingly been suffering under the shadow of death all of this time. It was only fair for them to reap the benefits of the victory first.
- As understood by Rabbi Jonathan Taub, Malbim notes that this is first time for the remainder of Megillas Esther that Shushan is not called Shushan HaBirah (which he translates as the palace compound). He answers that Esther wanted permission to kill in the city as they had in the palace.
- In a very different perspective, R’ Shimon Schwab writes that the verse mentions Shushan specifically because the Jews only killed there because they were afraid elsewhere. Esther wanted to show that faith is the thing that helps them. When the Jews do their part, H-Shem will do His part. He continues that this lack of faith is the reason for a Shushan Purim – it is a sign that the Jews in Shushan did not deserve to join the Jews in celebration on the same day.
- The Ben Ish Chai points out that Shushan (300+6+300+50=656) has the same gematria (and even same letters) as sason (“joy”) (300+300+6+50=656), which is what the Jews experienced (Esther 8:16) upon their miraculous rescue from obliteration.
- Furthermore, it is also the same gematria as lashon ra (“evil speech”) (30+300+6+50+200+70=656). Evil speech is what Haman tried to use (Esther 3:8) to defame the Jews before Achashverosh when requesting permission to exterminate them.
- Maamar Mordechai points out that, when the Jews were in Egypt, the ten plagues occurred for one month each. That being the case, the second to last plague, that of darkness, happened one month before Passover, which would mean it fell in Adar. Haman assumed the darkness was a plague that hurt the Jews since so many of them died then (see Rashi to Shemos 10:22 and 13:18). After all, four fifths of the Jews died in Egypt because they did not believe in their upcoming rescue. H-Shem killed these unfortunates during the plague of darkness to avoid the Egyptians seeing this, and assuming the Jews’ G-d is no longer with them.1 The Jews in Persia, by attending Achashverosh’s party, indicated that they, too, lost faith in their redemption, and this is why the lots falling on Adar so pleased Haman.
- Adar is also the month when Moshe died. According to the Talmud (Megillah 13b), Haman knew this because it is so written in the end of Devarim (34:8) and can be calculated from the book of Yehoshua. According to our tradition, the seventh of Adar, his date of death, is also his date of birth. Rabbi Mendel Weinbach writes that Haman did not know this because, as opposed to his date of birth, his date of death is only found in the Oral Torah.
- The Abudraham calculates that Adar 13 would mark the end of the seven-day mourning period (shiva) for Moshe. According to the Maharsha, that seven-day period of mourning continues in some mystical way the merits of the mourned. After that point, the dead only receive merit of others step up to take over their spiritual roles. Interestingly, Rabbi Dovid Feinstein notes that, Moshe having been born on 7 Adar, his bris (circumcision) would have been on 14 Adar, Purim!2
1It bespeaks a certain callousness that the Egyptians seemed not to notice the sudden disappearance of several million people.
2However, since Moshe was born complete and circumcised (Talmud, Sotah 12a), his bris would only require a symbolic pin-prick of blood called “hatafas dam bris” (Shulchan Aruch Yoreh Deah 262:1 and 264:1), and this procedure would not be help on a Shabbos (Shulchan Aruch Yoreh Deah 260:2 and 263:1). Therefore, Moshe’s symbolic bris was held on the following day, Shushan Purim.