The Vilna Gaon writes that the verse’s account of the Jews “doing what Mordechai wrote” refers to their giving charity and gifts.
Malbim explains that those Jews residing in the walled cities did not start to celebrate on their own, but only began when Mordechai’s decree went out.
M’nos HaLevi notes again that by writing it down, Mordechai retroactively transformed the Jews’ voluntary actions into the obligatory mitzvos of Purim.
R’ Dovid Feinstein adds that although the celebrations of Purim started on the Jews’ initiative, they submitted to the rule (and changes) of the sages.
The Dena Pishra writes that, at first, the Jews were upset with Mordechai for not bowing down to Haman (Esther 3:2), but now they recognized the wisdom behind Mordechai’s actions.
R’ Dovid Moshe Valle also points out that the Jews realized now that Mordechai had Ruach HaKodesh because he was able to summarize the events they witnessed into this multi-level text we have before us.
According to the Halacha (Shulchan Aruch Orach Chaim 695:4), each Jew is required to send two foods to at least one other Jew on Purim.
The Peleh Yo’Eitz notes that the best way to perform the mitzva is for a great person to give to a lesser member of society. This would create both joy and the potential for one mitzva to lead to others.
After all, as the Sfas Emes emphasizes, one of the intents behind this mitzva is to debunk Haman’s slander (Esther 3:8) that Jews are splintered. Besides, acts of chesed are the foundational groundwork for the rebuilding of the Beis HaMikdash (bimheira biyameinu).
Perhaps this is one reason for the Talmudic opinion (Megillah 7b) that one could also fulfill one’s obligation of mishloach manos by sending Torah.
Interestingly, Rav Shlomo Alkabetz wrote the oft-quoted M’nos HaLevi as a mishloach manos gift to his in-laws.
In Eparyon, Rav Ganzfried, author of the Kitzur Shulchan Aruch, considers mishloach manos as a cunning way to give charity. Since all people will be giving gifts to their friends, the poor would not feel embarrassed by accepting a handout. This also explains why the order of the mitzvos listed in this verse seems out of order, with the more important mitzva of tzedaka being mentioned last.
The Sha’arey Simcha writes that the reason for this order is that it is debatable which miracle was greater: the destruction of our enemies or the raising of the Jews. Therefore, there are two mitzvos, paralleling each of these miracles, respectively.
The Ohel Moshe notes that, as opposed to other Holy Days, where the mitzvos of the day (i.e. lulav, matza, shofar, etc.) are only relevant for those days, Purim’s mitzvos (i.e. tzedakah, chesed, learning Megillas Esther, etc.) are relevant all year long.
R’ Meir Yechiel of Ostrovtza says that the implication of the word “re’eyhu” (“his fellow”) is that every Jews is considered worthy of receiving mishloach manos on Purim in H-Shem’s Eyes.
The Chasam Sofer was asked if mishloach manos are Halachically for increasing unity or to help all Jews have the minimal means with which to celebrate. If it is for unity, then it is for the benefit of the giver; if it is to allow everyone to celebrate, it is for the receiver. A practical difference would be in a case where someone refuses to accept. In such a case, has the sender fulfilled one’s obligation? If it is for the giver, the answer is yes, whereas if it is for the receiver, the answer is no.
Once, when about to receive mishloach manos, the Brisker Rav looked outside to check if it was yet sunset, and thus no longer Purim. He was willing to accept mishloach manos for purposes of the mitzva, but was unwilling to accept it as a regular gift, in fulfillment of the words of the wisest of men (Mishlei 15:27) that one “who hates gifts lives.”
Regarding the unique language of this verse, the Ben Ish Chai notes that the gematria of manos (“gifts”) (40+50+6+400=496) is the same as the 50 cubits of Haman’s gallows with the word maves (“death”) (40+6+400=446), meaning that this mitzva is intended to remind us of Haman’s plan to kill Mordechai.
In his commentary on this verse, the Vilna Gaon writes that the expressions used in this verse refer to the four components of man – the nefesh (animus, ability to move), the ruach (life force), the neshama (spiritual soul), and the guf (physical body). He writes that the nefesh and guf are really one, as according to the Zohar which writes that “the nefesh is a partner to the guf.” Haman wanted to destroy every part of the Jew; he therefore used three expressions to denote his real intent. However, the neshama is fed by performance of mitzvos, the ruach is fed by pleasure, and the guf is fed by food. The Vilna Gaon writes that this is the reason for the three mitzvos of Purim; publicly reading the Megillah (see Esther 8:26) feeds the neshama, having joy (see Esther 8:17) feeds the ruach, and feasting (ibid.) literally feeds the guf. There is also an extra mitzvah of giving gifts (ibid. 19). Perhaps Haman’s desire to plunder the Jews’ wealth is the reason we use our resources for this last mitzvah.
R’ Dovid Chadida writes similarly that by using the word “l’hashmid” (“to destroy”), Haman intended to kill the Jews spiritually, by using the word “l’harog” (“to kill”), Haman intended to kill the Jews’ physically, and by using the word “l’aveid” (“ to annihilate”), Haman intended to kill the Jews’ financially. In the verses of Shema (Devarim 6:5), these are the very three things with which Jews are expected to dedicate themselves to love H-Shem.