"A person is obligated to drink on Purim," says the Talmud, "until he does not know the difference between 'Cursed be Haman' and 'Blessed be Mordechai'"

There are different types of joy. There is "the joy of mitzvah," for a Jew is commanded to "Serve G‑d with Joy" (Psalms 100:2). A mitzvah performed joyously is greater, deeper, more alive, than a mitzvah performed mechanically. This joy, however, is not an end in itself, but for the sake of enhancing a mitzvah.

Another type of Jewish joy is the mitzvah to "Rejoice in your festivals" (Deuteronomy 16:15). Here, joy is not an accessory to another aim. The mitzvah itself is to rejoice.

But the fact that one needs to be commanded to rejoice indicates that this is still not the ultimate in joy. A greater joy is one King Solomon speaks of when he says, "The good-hearted is festive always." (Proverbs 15:15), describing joy as a state of being rather than an activity. This is the joy experienced in the month of Adar—in the words of the Talmud, "When Adar commences, joy increases." One who is attuned to the spiritual essence of Jewish time spontaneously rejoices when entering the month of joy.

Still, this is a conscious joy, and the very fact that a person is aware that he is rejoicing indicates that his joy is an assumed state rather than an intrinsic condition. The acme of joy is attained on Purim, when the Jew celebrates "until he does not know." So thoroughly does the joy of Purim permeate the soul of the Jew, that he doesn't even know that he's rejoicing!