There is a Midrash that has perplexed many Torah scholars. In the Megillah (Book of Esther) we read, "These days of Purim will never cease among the Jews" (9:28), upon which the Midrash says, "All the other festivals are destined to fall away, but Purim shall always remain" (Shochar Tov, Mishle 9). How can this be? We know that nothing in the Torah will ever be obsolete? How can the Midrash say that there will be no observance of Passover, Shavuos or Sukkos? Various interpretations have been offered, but it still remains enigmatic. However, one thing is clear: Purim is of extraordinary importance. Indeed, some sefarim say that Yom Kippur, which the Torah refers to as Yom Kipurim, means that it is a day similar to Purim. The holiest day of the year, yet it is only "like" Purim.
Rebbe Levi Yitzhak of Berdichev in Kedushas Levi says that the miracle of Purim indeed surpasses the miracles commemorated by the festivals. The ten plagues in Egypt, the dividing of the Reed Sea, the daily manna (and a double portion on Friday), the clouds of glory, and the revelation at Sinai were all manifestly supernatural phenomena, easily recognized as the handiwork of Hashem. The sea does not split of its own accord. There was no challenge to emunah, but after the miracles ceased, our ancestors backslid into idolatry, as is clear in the works of the prophets. Miracles are indeed very impressive, but their effect may not endure.
The first of the Ani Maamin, the Thirteen Principles of Faith formulated by Rambam, is "I believe with perfect faith that the Creator, Blessed is His Name, creates and guides all creatures, and that He alone made, makes and will make everything." With the exception of moral behavior, in which we have bechirah (free choice), in which Hashem does not intervene, everything is the work of Hashem.
In our prayer we say, "We shall thank You and relate Your praise for our lives, which are committed to Your power and for our souls that are entrusted to You, for Your miracles that are with us every day." Miracles every day? What miracles? We do not see supernatural happenings every day.
King David says, "To Him Who alone performs great wonders" (Psalms 136:4). The Talmud explains "alone" to mean that only Hashem knows the great wonders He does. "The beneficiary of a miracle does not recognize the miracle (Nidah 31a). The problem is that we tend to believe that things happen "naturally" or that we make them happened. Moses warned us, "You may say in your heart, ‘My strength and the might of my hand made me all this wealth!' Then you shall remember that it was Hashem who gave you strength to make wealth" (Deuteronomy 8:17). The Midrash says that one should praise Hasem for every breath, because with each breath we are given new life (Bereishis Rabbah 14).
At the Exodus, we indeed saw many miracles. We were then given the mitzvah of matzah on Passover. The prohibition of chametz is unique. For all other forbidden foods, the halachah is that if non-kosher food happens to get mixed with kosher food, and the ratio of kosher to non-kosher is greater than 60 to 1, the food may be eaten. This is not true of chametz on Passover, where if a tiny morsel of chametz falls into a great vat of food, so that the chametz is less than one millionth, all the food is forbidden. Why is the prohibition of chametz so severe?
Bnei Yisaschar explains the difference between matzah and chametz. With matzah, from the time the flour is mixed with water, someone is at all times processing it. It is kneaded, rolled, perforated and baked. The dough is never left alone without someone doing something with it. Not so with chametz, where after the flour and water are mixed, it is set aside for several hours to rise by itself. In the formation of chametz there is spontaneous action, without anyone doing anything to make it rise. Matzah, therefore, expresses the concept that nothing happens on its own, not even the tiniest of tiniest thing. There is no spontaneity. Hashem is directing and manipulating everything.
This teaching was given to the Israelites at the Exodus, to know that the slightest occurrence in the world is as much the direct handiwork of Hashem as the dividing of the Reed Sea.
This is why the miracle of Purim is more important than the miracles commemorated by the festivals. There was nothing supernatural about Purim, yet everything was being orchestrated by Hashem to bring about the salvation of the Jews.
What happened? The king got drunk and was infuriated by the queen's refusal to obey him, so he had her executed. Hardly a supernatural miracle. It is possible that the following day, a Jew said to his friend, "Did you hear what happened at the palace yesterday? The king was drunk and had the queen executed." The friend may have responded, "Why are you telling me this foolishness." Foolishness! This was Hashem's way of preparing for the salvation of the Jews, but no one was aware of this. This was just something natural.
There is a palace intrigue to assassinate the king. This is discovered by Mordechai, and he reports it to Esther. The king wishes to reward the person who saved his life, and Haman assumes that he is the one to be honored, but instead has to lead a parade honoring his arch enemy, Mordechai. Nothing supernatural about this.
Every little event in the story of Purim was Hashem at work, but this just wasn't apparent. The Purim story conveys the basis of our faith, as Rambam states that "I believe that Hashem alone made, makes and will make everything." That every single thing that happens in the world is under the direct management of Hashem, that is the teaching of Purim, and that is why it is of greater importance than Passover, Shavuos and Succos.