23. And the Yehudim accepted that which they began to do and that which Mordechai wrote about them.
In a simple explanation, the Ibn Ezra writes that the verse uses the singular “v’kibel” (“and accepted”) in order to mirror Aramaic grammar.
However, the Vilna Gaon, Lekach Tov, M’nos HaLevi, Beis Aharon, R’ Moshe Dovid Valle, and the Maharal all write that the verb is in singular because all of the Jews were united.
The Zohar (II:113b) explains that the Jews trusted Moshe and accepted the Torah, and reaffirmed it at this point. Although Moshe was one man, the Jews’ re-acceptance of the Torah he taught became attached to him, thus necessitating a singular verb.
22. Like the days on which the Yehudim rested from their enemies and the month which was switched for them from sorrow to joy and from mourning to holiday to do on them days of feasting and joy and sending gifts each man to his fellow and gifts to the poverty-stricken.
According to the Talmud Yerushalmi (Megillah 1:4), the verse uses the phrase “the month on which changed…” instead of explicitly using the name, Adar, because if Purim theoretically fell on Shabbos (as was possible before Hillel the Younger developed our calendar system), not to mix the rabbinic holiday of Purim with the Torah-level obligations of Shabbos. Although it would not push off our obligations on that day, they would be somewhat compromised. To emphasize that the important aspect of this is the month when this event occurred, the verse does not state the fact that it is Adar.
Furthermore, the Talmud Yerushalmi (Megillah 1:1) also says that the entire month is fitting for Megillas Esther to be read publicly.
The Vilna Gaon notes this is why the Talmud (Taanis 29a) famously says that when the month of Adar (and specifically not Purim) comes in, we increase our joy.
The Ibn Ezra says that part of the reason for this is that sometimes Purim is not Adar, but rather in Adar Sheini. If the verse would have explicitly said Adar, Purim would have to be in the first Adar during leap years.
The Maharal emphasizes that Haman was so overjoyed when the lot fell on Adar because it is the last month of the Jewish year, and has the spiritual potential to be an end, in the negative sense.
R’ Chaim Kanievsky explains that the verse’s focus is on reversal because H-Shem can reverse anything, even those astrologically set “times.” After all, Haman’s choice of Adar as the month to attack the Jews was partially due to our supposed spiritual vulnerability.
And Mordechai wrote these things and sent books to all of the Yehudim
in all of the states of King Achashverosh, the near and the far.
Malbim says that what Mordechai wrote were the details of what occurred, since he was concerned that Jews outside of Shushan knew very little about the miraculous success of the Jews of Shushan.
According to Rashi, what Mordechai wrote is the content of Megillas Esther, exactly as it appears today.
The Ibn Ezra wrote down the reason for the previously mentioned joy.
Pirkei d’Rebbe Eliezer writes that Mordechai wrote this down as the head of the Sanhedrin.
The Vilna Gaon explains that this means that he wrote the Halachic details of how to properly commemorate Purim, with what can and cannot be done on this day.
R’ Dovid Feinstein emphasizes that Mordechai is making the changes for the holiday that the Jews had accepted upon themselves spontaneously.
R’ Elisha Gallico notes that it is so important to remember the real source of Purim, there are two readings of Megillas Esther every Purim. This is why Moredechai did not make Purim an actual Yom Tov in order to allow the Jews to perform the other mitzvos of the day.
The Oznei Yehoshua notes that if we had Purim without its rules, we would end up having an empty, meaningless holiday. As it stands, Purim is the epitome of giving in the Jewish community.