Why Do We Wear Costumes on Purim?

Purim is possibly the most fun holiday of the year and according to our Sages, even holier than Yom Kippur. The name Yom HaKippurim implies that Yom Kippur is a day like Purim but not as holy as Purim.

Purim commemorates the day that the Jews accepted the Torah upon themselves, but this time out of pure love. When we received the Torah at Mount Sinai, G-d threatened us with death by putting Mount Sinai over our head and saying "it will be good with you, if you accept this Torah, and if not, this mountain will be your death." We accepted the Torah then with love but also out of fear.

In the days of King, Achashveirosh, we accepted the Torah out of pure love for the miracle that was done for us. See Rashi

There are a few reasons given why we have the custom of wearing costumes on Purim:

The custom of wearing costumes on Purim is an allusion to the nature of the Purim miracle, where the details of the story are really miracles hidden within natural events.

The Talmud writes that just as the Jews at the time pretended to be serving other gods, G‑d pretended that He was going to destroy the Jewish nation, and in the end He did not. Rabbi Tzvi Elimelech Shapiro (1783–1841), known as the Bnei Yissaschar, writes that this is the reason we pretend to be someone else on Purim, since both the Jews’ and G‑d’s actions were masked by other intentions.

We dress differently on Purim to minimize the embarrassment of the poor who go around collecting charity on this day—a day when we give charity to everyone who outstretches their hand.

To commemorate the dressing up of Mordechai in King Achashveirosh's royal garments in the story of Purim.

I would like to add another reason to why we dress up in costumes on Purim,

The entire year we are not our real selves. As much as we want to be ourselves, we care about public opinion, we care about what others think about us, we think about how G-d wants us to act and how He is always watching us. On Purim, we let go of being actors on the world stage, and for one day we live who we really are. We drink wine to relax, to put our guard down, For one day a year, G-d says, "Today, be yourself!" Not only are we allowed to be ourselves, but we are rewarded for being ourselves! There is the mitzvah of making a feast on Purim and not only do we get drunk on the wine and eat a festive meal, but we get rewarded for it.

How great is the G-d of Israel who in His mercy says "Today be yourself and I will reward you for it."

We wear costumes because for 364 days of the year we are fakers and people pleasers. We care about what others will say or think about us. For one day of the year, to be our true selves is difficult so we hide behind a mask, a facade. Ironically, as we we hide behind this mask, we become and act for who we really are.

Wine which is yayin יין in Hebrew equals 70 in Gematria. The word for secret, sod סוד is also 70. You can only have 70 in you so when the wine goes in, the secrets come out. This is one of the reasons we drink on Purim. To be ourselves. Being ourselves is liberating and healthy. (And fun!)

It is a great exercise the day after Purim to do a cheshbon hanefesh, i.e. soul searching and study how your behavior was during Purim. If you don't remember, ask. But in general we will remember if we were happy, or sad, or clowns, or destructive, or a nuisance, or a joy to be around, or a dancer, or if you couldn't stop talking Torah! Doing this soul searching and being honest with the results will let you know if you are where you want to be or if you're playing the part of someone you really are not and need to work on yourself to truly be this person.

Wishing everyone a happy and safe drinking this Purim! L'Chaim!