(1) And so, on the thirteenth day of the twelfth month—that is, the month of Adar—when the king’s command and decree were to be executed, the very day on which the enemies of the Jews had expected to get them in their power, the opposite happened, and the Jews got their enemies in their power.

(22) the same days on which the Jews enjoyed relief from their foes and the same month that had been transformed for them from one of grief and mourning to one of festive joy. They were to observe them as days of feasting and merrymaking, and as an occasion for sending gifts to one another and presents to the poor.

(22) Ben Bag Bag said: Turn it over, and [again] turn it over, for all is therein. And look into it; And become gray and old therein; And do not move away from it, for you have no better portion than it.

Rav Ashi strongly objects to this: On the contrary, the opposite is more reasonable. Nine people who ate together appear like ten, so even if one is missing, the quorum does not seem to be incomplete. Two people who ate together do not appear like three, so it would be reasonable to require the actual presence of the third.

(5) A woman must not put on man’s apparel, nor shall a man wear woman’s clothing; for whoever does these things is abhorrent to the ETERNAL your God.

The custom of wearing masks on Purim, and of crossdressing, is totally permitted because of its innocent and joyful purpose, as is the wearing of shaatnez. While some would prohibit it, our practice is as I have already said. So too those who playfully rob each other do not violate "Thou shalt not steal'', and such is our custom. However, you may do only as local elders permit. (Responsum of Mahari Minz #17).

Esther sent a message to Mordecai: “Go, gather together all the Jews who are present in Shushan, and fast for me, and neither eat nor drink for three days, night and day; I also and my maidens will fast likewise, and so will I go in to the king, not according to the custom” (Esther 4:16). Rabbi Abba said: It will not be according to my usual custom, for every day until now when I submitted myself to Ahasuerus it was under compulsion, but now I will be submitting myself to him of my own free will. And Esther further said: “And if I perish, I perish” (Esther 4:16). What she meant was: Just as I was lost to my father’s house ever since I was brought here, so too, shall I be lost to you, for after voluntarily having relations with Ahasuerus, I shall be forever forbidden to you.