Esther had not made known her people nor her kindred; for Mordecai had charged her that she should not tell it.
Now it came to pass on the third day, that Esther put on her royal apparel (tilbash malchut), and stood in the inner court of the king’s house, over against the king’s house; and the king sat upon his royal throne in the royal house, over against the entrance of the house.
And I (God) will surely hide (astir) My face in that day for all the evil which they shall have wrought, in that they are turned unto other gods.
Rabbi Mishael Tzion:
Purim invites us to set aside a time in which we completely reverse our wardrobe, which in turn reverses our identity. It is an invitation to cross dress, but not only to cross genders (the classic Purim costume, mentioned in many collections of Rabbinic customs), but to cross and reverse all the other dichotomies and uniforms of our lives as well. On Purim we are using clothes against themselves, to deny their power to box us in, and simultaneously to redeem us from needing redemption. At its scariest hours, Purim, like the good carnival that it is, makes us wonder if there is an "authentic self" at all, or whether it is all just endless masks upon masks.