The Midrash (Esther Rabba 10:10 and a number of other Midrashim) teaches that the turnaround mentioned in this verse refers to all of Haman’s plans – from the queen whom Haman installed for more power taking his power, to the tree he prepared for Mordechai becoming the one on which he was hanged, to the wealth he gathered becoming Mordechai’s property, to the honors he wanted being given to his enemy, to the date Haman picked for the Jews’ extermination becoming the date of their success – absolutely everything backfiring.
The Kol Reena points out that the reason for Haman’s thinking of Adar as the ideal month to wipe out the Jews was that Moshe died on that month. Ironically, Moshe’s merits are what protected them.
R’ Hutner notes that even the misuse of Temple vessels (Esther 1:7) in order to show that it would never be rebuilt was turned around because the Purim story led to the Beis Hamikdash being rebuilt.
The Dubno Maggid writes that this turnaround shows how much hate Haman had. After all, the Talmud (Brachos 7a) teaches that we can see the evil that Bilam intended from the diametric opposite good with which he blessed the Jews. Here, too, Haman’s hate can be seen from the positive turnaround that resulted.
The Maharal notes a principle of physics that when one throws a rock against a wall, it bounces back somewhat. One could measure the level of Haman’s hate from the force with which Haman was punished. As the Torah (Devarim 19:19) commands regarding false witnesses, Haman got back an equal measure of what he intended against the Jewish people.
The Dubno Maggid also writes that Haman’s failed decree exposed the Jews’ enemies, who likely gathered arms in preparation for the attack, and this effectively made it easier to expose these Jew haters. Similarly, Yehu gathered together worshipers of Baal by promising a demonstration of his tremendous worship as a ruse to capture them and punish them for idolatry (Melachim 2 10:19).
R’ Shmuel Aharon Rubin writes that when the Talmud (Megillah 10b) says “we were slaves, but H-Shem did not abandon us,” it is in relation to the Purim story. He explains that we were like slaves because the Talmud (Kiddushin 36a) says that the Jews are called the children of H-Shem when they fulfill His Will, and are called slaves when they do not. The Jews’ attendance at Achashverosh’s feast demonstrates that they were not fulfilling H-Shem’s directive, but He nevertheless “did not abandon” the Jews.
R’ Hutner adds that since the existence of the Jews is without limit, rejoicing on Purim is also without limit. There is a famous story of a friend of mine who had gone missing the day after Purim. He was eventually found on a Sunday night after he had fallen on a hike on Friday. Without nutrition since Friday, he was only able to survive because the day previous was Purim, and the person sitting next to him at the Purim seudah kept piling food onto his plate to encourage him to eat without restraint in fulfillment of the above dictum.
- Besides stressing that the verse mention that the gallows were prepared “for him,” R’ Shlomo Kluger in Ma’amar Mordechai points out that in order to be consistent with Zeresh’s advice earlier (Esther 5:14), the verse should have written “asher asa lo” (“that he made for him”) instead of “asher heichin lo” (“that he prepared for him”).
- The Talmud (Megillah 16a) explains that the gallows Haman had built were prepared in the ironic sense that they would unintentionally be used for his own hanging.
- The Vilna Gaon explains that, as opposed to something whose purpose changes, the gallows were never meant for Mordechai at all, and were always for Haman. Some things historically had an intended purpose, and were then appropriated for some other use. T.N.T., for instance, was meant to be used solely for construction. Its being adopted for use in war so traumatized its inventor, Alfred Nobel, that he developed the Nobel Peace Prize for those who allegedly bring peace to the world. These gallows, by contrast, from their inception, were always intended for Haman’s downfall.
- R’ Dovid Feinstein explains that the gallows had to be a perfect fit for Haman, since he and his sons all fit on the same gallows (see Targum Sheini to Esther 9:14). See attached chart.
- According to the opinion that the gallows were made from the beams of the Beis HaMikdash, the Ben Ish Chai asks how Mordechai could have the right to use them as he will when he hangs Haman (Esther 7:10) since he would thereby desecrate these holy objects (Pirkei D’Rebbe Eliezer 50). However, answers the Ben Ish Chai, Haman’s using the beams first took away their sanctity, preparing the beams for use in his own death.
- Using Newtonian physics, the Maharal points out that if an object that is thrown at a wall drops straight down upon impact, this shows the amount of force applied by the thrower. However, if the object bounces back upon impact, this means the thrower applied more force, and it was only the wall’s strength that kept the object from its intended place. Similarly, in yet another example of mida kineged mida, what happened to Haman (and his sons) reflects the vehemence with which they planned to dispatch Mordechai.
- According to R’ Yehonason Eibshutz in Yaaros Dvash, Haman intended hang a completely different “him” – the king. After all, Haman had planned a conspiracy to take over the monarchy.
- On a Halachic point, the Chasam Sofer notes that hachana (“preparation”) usually implies in the legal world preparing for the next days. In this case, where Haman prepared the gallows earlier that morning, why is this hachana for the same say? He answers that hachana for gentiles does not need to be for the next days since the Talmud describes them as “holech achar hayom,” that they follow a solar schedule, controlled by the sun.
- The Belzer Rebbe adds that Halacha recognizes the need for mitzvos to have hachana; this is not true for sins. For example, consider how much planning you needed to put into learning right now, versus how much planning you would have needed to waste your time in front of a tv or computer screen, instead. Therefore, the gallows must have been for Haman since killing out the nation of Amalek is a mitzvah (Rambam, Mishneh Torah, Hilchos Melachim 6:4).