Answer: Purim is the exposure of our previous states because each of us is actually evil! We masquerade as different figures both wicked and righteous: On one hand as Haman and Ahasuerus, and on the other as Mordecai and Esther. Purim is a carnival. We hide our faces behind masks because it is about the revelation of goodness and evil when you totally lose your identity, your face, and cannot tell the wicked from the righteous, because they are totally mixed and support each other as we move towards the Creator.
It is actually by the right combination between the wicked and the righteous that we attain adhesion, connection, closeness, equality, and identification with the Creator. We can masquerade as anything and even several times. We can wear a double costume: a mask of a righteous in the front and a mask of a wicked from behind, or vice versa. Purim is the last correction of humanity from evil to goodness when the absolute evil is revealed and changes into goodness.
From KabTV’s “News with Michael Laitman” 3/16/16