The Gemara tells us that the terrible decree to destroy the Jewish people was a punishment for their partaking of the banquet of Achashveirosh . Throughout the period of the first Beis HaMikdash, the Prophets were rebuking the Jewish people for terrible sins, including Avoda Zara, and yet they were never sentenced to universal destruction - why was such a drastic punishment reserved for the seemingly mild aveiro of eating at Achashveirosh’s banquet?
In order to answer this question let us first discuss the intentions of Achashveirosh in throwing such a lavish banquet. Chazal tell us that the drinks were served in the keilim that were used in the Avoda in the Beis HaMikdash. The King even dressed himself in the clothes of the Kohen Gadol - what was he trying to achieve by doing this? Rav Chaim Halpern Shlita explains that up till this point in time, Achashveirosh had been worried about the prophecy of Yeremyahu that the Jewish people would return to Eretz Yisroel and rebuild the Beis HaMikdash after 70 years. The King calculated that the 70 years had now passed without any sign of the prophecy being fulfilled. Consequently, on the exact day that he had calculated that the time was up he held the feast - he was trying to tell the Jews that they should give up hope of the Beis HaMikdash and that they now had an alternative source of happiness - his Kingdom. Therefore, he dressed up as the Kohen Gadol to show that he was their new leader, and he gave them the Temple vessels to show them that there was no point in waiting any longer for the Beis HaMikdash to be rebuilt .
Unfortunately, the Jewish people accepted the King’s message and willfully joined in the Seuda, even drinking from the Temple vessels. They gave up hope - they terminated their desire for a Second Beis HaMikdash, and turned to a new future, being loyal subjects of the King and his Empire. What in effect they had done was give up on the unique role of the Jewish people as the Chosen People who were meant to serve as a Light Unto the Nations. They forsook any hope of a return to Eretz Yisroel and a new Beis HaMikdash. What they did not realize is that the Jewish people’s whole right to existence is based on their unique role in the world. Hashem cherishes the Jewish people because of its willingness to serve as an Am Segula who teaches the world to know Him. Now that they did not want to assume this unique role they automatically forsook any right to exist. Measure for measure, they were sentenced to destruction .
How did the Jewish people overturn the decree of destruction? The Gemara tells us the conversation that took place when Haman came to inform Mordechai of the honor that the King wanted to bestow on him. Haman found Mordechai learning Torah: Haman asked, “What are you learning?” Mordechai answered, “When the Beis HaMikdash existed, a person who gave a Mincha offering would bring a handful of flour and it would atone for him.” Upon hearing this, Haman replied, “your handful of flour will come and overturn my ten thousand silver shekalim. ” This Gemara is very difficult to understand - what was the significance of what Mordechai was learning and why did it make Haman realize that he would be defeated? The Ponevezher Rav explains that Haman knew that his hope of success lay in the defeatism that the Jewish people expressed at the Seudas Achashveirosh. He saw that Mordechai was teaching about laws that only apply when the Beis HaMikdash is standing - he realized that the Jewish people had done teshuva and reignited their desire for a new Beis HaMikdash. They still had hope that they could continue in their unique role as the Light Unto Nations, and consequently Haman knew that if they had not given up on Hashem then He would not give up on them.
The nisayon of the Jews in the time of Purim was to maintain hope during trying times. This nisayon continues to this very day and when we demonstrate weakness in it, our enemies gain encouragement that they can defeat us. The story is told of an infamous Arab terrorist who discussed the time he spent in an Israeli prison, after which he resumed his evil activities with even greater zeal. He said that, whilst in prison, he had initially decided to renounce his ‘career’ as a terrorist, feeling that his violent actions could not succeed in destroying Israel. However, one Pesach, he saw an Israeli guard eating a pitta. Knowing about the issur of eating chametz he inquired as to why the Jew was not observing this law. The Guard answered him that these laws are no longer of any importance. Hearing this, he decided that a people who had given up on their heritage could indeed be defeated. In stark contrast, after Napoleon had conquered yet another nation, he was shocked to see that the Jews were in grief. They explained to him that it was Tisha B’Av and they were mourning the destruction of the Temples. He asked them when this occurred and they explained that it was nearly 2000 years earlier. Upon hearing this he exclaimed that a people who kept such a strong connection to their heritage would surely never be destroyed.
We live in a time where the test of yeush exists on many different levels. For non-observant Jews, the test is obvious - not to completely abandon their heritage by assimilating into secular culture. But the nisayon applies to everyone in some form: Firstly, one may be tempted to give up on the millions of secular Jews, arguing that they are irretrievably lost to assimilation. This is of course a highly erroneous attitude and experience has proven that secular Jews can be quite easily reconnected to genuine Judaism. A second nisayon is that keeping the mitzvos does not necessarily preclude yeush - indeed the Jews who ate at the King’s banquet were still makpid only to eat kosher food. A person can keep mitzvos and still wonder if there will ever be a Third Beis Hamikdash and if Mashiach will really come. Moreover, yeush can plague our personal lives, persuading us that we have no possibility of achieving greatness. The story of Purim teaches us that we need never give up hope, both for the Jewish nation and ourselves as individuals - and as long as we maintain our desire to be the part of the Am Hashema we can be assured that He will protect us from all of our enemies.