Jewish holidays are more than the celebration and remembrance of historical and spiritual events. They are also an institutionalization of the spirituality of the various seasons in nature (at least in the northern hemisphere). For example, Pesach is a holiday of rebirth, which is what occurs in nature in the spring, Sukkot is a spiritual preparation for the winter, and Channukah is a mobilization of light during the longest nights of winter.
It should be viewed as no coincidence, then, that Purim falls out in the month of Adar, a month of transition from winter to spring. It is perhaps to this that Chazal were alluding when they identified Esther with the Ayelet haShachar, the morning star, the star that signals the beginning of the transition from night to day(1). As we will see, the daily unfolding of the morning light thematically parallels the transition from winter to spring.
Megillat Esther clarifies the spiritual message of the transition to spring. We see a battle between two extreme worldviews played out on the turf of a third in-between worldview. The two extreme views are represented by the nations of Amalek and Yisrael, and the middle view is Zoroastrian Persia. All three aim to deal with the problem of theodicy - why evil happens if G-d is good. Zoroastrianism deals with the problem by saying that there is actually a second god who is responsible for evil. Amalek's approach is to deny one premise of theodicy, the goodness of G-d. And Yisrael's position is to ultimately deny the other premise, the actual existence of evil in the world.
By denying G-d as normally defined, Amalek understands the world as ultimately chaotic and so Haman, the representative of Amalek, goes out of his way to make sure that the annihilation of the Jewish people will be determined by the random nature of the pur, the lottery. The megilla, in turn, mocks this approach by showing the Divine imprint in all of the supposedly random events in the story.
The Jewish people's viewpoint about evil (i.e. chaos) - that it is an illusion - is most clearly portrayed by Rabbi Akiva, who declares that everything G-d does (including that which appears chaotic), He does for the good(2). In other words, bad things are really to our benefit even when we do not find out why. While in the famous Talmudic story the reader is able to see how the calamities that Rabbi Akiva encountered were to his ultimate benefit, it must have been equally clear to Rabbi Akiva that we generally do not have such opportunities to see how calamities benefit us.
More than any other month, Adar shows the truth of the Jewish worldview as propounded by Rabbi Akiva. To someone unaware of spring, winter appears to be a manifestation of evil or chaos, something that the Zoroastrians may have attributed to the rival god of evil. After all, if one goes out to the field, all one perceives is barrenness and cold. To the uninitiated, the trees stripped of their leaves appear dead - there are no visible signs of life. And yet it is precisely the wet weather of winter that allows for the beauty and fertility of spring. Usually, the more miserable and wet the winter, the more productive the spring. In Adar, when we see the various blossoms and flowers all breaking out of their winter hibernation, we are able to give meaning to the desolation of winter.
An even starker example of this process, whereby one sees the very necessary contribution of what could otherwise be seen as chaotic, is the forest fire: It does not just appear to kill beautiful vegetation, it actually destroys living organisms. Nonetheless, forest fires are actually good for forests, in that they get rid of sick and decaying vegetation and allow for the forest to actually rejuvenate itself into a stronger, healthier entity.
We find the meaning of Nature's transition reinforced by another theme of Purim - the concept of joy, which is at the heart of our celebrations. Simcha - joy - as manifested through laughter is an appreciation of complexity. This very contrast is what makes us laugh at jokes. A pun or double entendre is the simplest example of this. Likewise, a comedian dares not give away the punch line, since the humor comes in the unexpected - what gives the punch line its punch is its contrast to the apparent story line.
When we look at Nature unfolding from the death of winter to the colors of spring, there is room for joy and laughter. This laughter is in appreciation of a reality that goes beyond our expectations. I remember a fellow yeshiva student who would laugh when he saw a seed sprout - he would laugh at how this apparently dead object sprang forth to life. By setting up the world in this way, G-d shows us the meaning of Rabbi Akiva's statement that everything that G-d does is for the good - that even what appears evil or chaotic is really an essential means to attain the good.
Rav Dessler(3) writes that when Chazal tell us we need to increase our joy, they are talking about building successive levels of joy. It would appear that this is, in fact, the message of the morning star, the Ayelet haShachar. Things occur in gradual processes. Just as the morning star is the first sign of the process that takes us from night to day, so too Adar is a process that takes us from winter to spring. As the natural world increasingly unfolds its colors, we can increasingly appreciate G-d's presence in the world and dismiss the problem of theodicy.
It appears that Purim sets up the spiritual paradigm of our days and, even of the end of days. Chazal points out that this is the way of the ultimate redemption. It is a process that begins slowly (4) - a process that allows us to gradually prepare our receptivity to the spiritual grandeur of the days of Messiach. Those who expect Messiach to simply show up out of the blue are mistaken. Rather, it is up to us to start the process even after the spiritual decimation of the last two centuries. It has been said that the Ayelet haShachar comes out when the sky is darkest.
1 Yoma29 - While several other possibilities are offered by the Babylonian Talmud, the Yerushalmi in Berachot 1:1 seems to indicate such a comparison. See also Anaf Yosef in Ein Yaakov on R. Asi's position in Yoma.
2 Berachot 60.
3 Michtav MeEliyahu vol.2, p.123.
4 Yerushalmi, Berachot 1:1.