Costumes on Purim
There's no doubt that one of the most exciting features of Purim, especially for children, is that of dressing-up and wearing costumes. The Talmud[1] teaches that wearing costumes on Purim is actually alluded to in the Torah.[2] This is based on the fact that the name “Esther” actually means “hidden” in Hebrew, which is the source for the custom of "hiding" one’s true self on Purim. It is interesting to note that there have been authorities in the past who opposed the custom of dressing-up on Purim, though this opinion was never widely accepted.[3] There are also those who rule that one should wear Shabbat clothes on Purim rather than a costume, at least for the Megilla reading.[4] Although cross-dressing is generally forbidden,[5] some authorities permit one to do so on Purim as long as it is done in good taste.[6]
Another reason we wear costumes on Purim is because there is no direct mention of God anywhere in the book of Esther. As such, one could mistakenly believe that the salvation from Haman's evil plot was merely a string of coincidences and good timing. The costumes remind us of God's "hidden" providence and miracles in the world.
We are taught that in the days of Mordechai and Esther the Jewish people repented from their sins, which was what aroused God to come to their assistance. Hence, the costumes remind us that one can easily change oneself to something better should one truly desire to do so. So too, when a Jew sins, he is actually "hidden" in a sense, as it is not the nature of a person to want to sin.[7]
Some have the custom to wear royal-themed costumes on Purim which is intended to recall that Mordechai and Esther were both dressed in royal garments at one time or another in the Purim story. Wearing such costumes also serves to remind us that every person has the potential to become great and rise to a level similar to that of royalty.[8] One should not dress-up in a manner that will raise security concerns, fear, or suspicion, especially in Israel.[9]
There are those who connect the custom of wearing costumes to the charity aspect of the holiday. Purim is a day when charity is to be distributed so lavishly that one should give money to all who come asking for some. In fact, one is not even to ask charity collectors how the money will be used.[10] As such, costumes were used as a means for charity collectors and other beggars to conceal their identities and better maintain their dignity.[11] It is interesting to note that Gentiles began to take advantage of the Purim generosity and would dress-up in costumes in order to collect money for themselves. As a result of this development it became customary to only dispense charity money to those who would request it in Hebrew or otherwise offer a sign that they were Jewish.[12]
[1] Chullin 139b.
[2] Devarim 31:18.
[3] Rema, OC 696:8.
[4] Mishna Berura 695:3; Kitzur Shulchan Aruch 141:4; Minhagei Eretz Yisrael (Gellis) 35:14.
[5] Devarim 22:5.
[6] Rema, OC 696:8, Mishna Berura 692:30. For an opposing view see Yabia Omer, YD 5:14:3.
[7] Midrash Rabba, Emor 30:3.
[8] Elya Rabba, OC 696.
[9] Devar Chevron 2:650.
[10] OC 694:43.
[11] Minhag Yisrael Torah, OC 696.
[12] Nitei Gavriel, Hilchot Purim, birurim 7.