Mordechai said: “The wealthy person has no problem observing Yom Tov, he has money. But the poor man – if you tell him not to work, what will he eat? He earns a daily wage; no work means no money, no feast.” Mordechai said: “Don't worry – Matanot La'evyonim. Others will give tzedakah to the poor, and they will have money for the feast.” As the Alsheich writes:
ִהְיֶה לָהֶם... כְּדֵי שֶׁיִּהְיֶה לָהֶם מִמַּה לַעֲשׂוֹת סְעוּדָה – נָתַן אֶת הַמַּתָּנוֹת לָאֶבְיוֹנִים.
The hardship of ceasing from labor falls only upon the poor and destitute. So that they would have the means to make a feast, he established Matanot La'evyonim.
In years past, Mishloach Manot actually served the practical purpose of providing for the Purim feast. When I was a child, my mother, aleha hashalom, would send cooked food to the neighbors – stuffed cabbage and various other dishes – and the neighbors would send back kugel, p'tcha, and all kinds of other foods. You sat at the Purim table and the food came from the entire neighborhood! In our generation, Baruch Hashem, everything has become somewhat synthetic – the package you sent in the morning has made a full circuit of the block and returned to you by evening! And of course everyone has their own dietary requirements: one doesn't eat sugar, one doesn't eat salt, and one avoids gluten. In earlier times everyone was healthy and perfectly fine.
The Gevul Binyamin also explains, since we were saved from death itself, in the time of the Beit Hamikdash we would have brought a Korban Todah – a thanksgiving offering. But we have no Beit Hamikdash standing, so how do you thank Hashem?
עֲשֹׂה צְדָקָה וּמִשְׁפָּט נִבְחָר לַה' מִזָּבַח – To do justice and judgment is more desired by Hashem than sacrifice (Mishlei 21:3). Since we were saved from death, we give the equivalent of a Korban Todah through Matanot La'evyonim.
