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).
The Midrash (Esther Rabbah 9:2) writes that Haman had 365 advisers, one for each day of the solar year. None of these could advise Haman as cruelly as Zeresh, his wife. She mentions many miracles performed for the Jews to save them from various forms of death, including fiery furnaces, lions’ dens, and the desert. She points out that hanging is the one form of killing from which no Jew had ever been saved. Foolishly ignoring that this method had never been attempted either, and that the Jews have been saved miraculously from far more menacing dangers, Haman accepts the advice and begins immediate construction of a hanging tree (Esther 5:14).
According to Rebbetzin Tzipporah Heller, Esther planned for the next party to specifically occur the next day in order to “intensify the effect of her plan.” This would make the tension between Achashverosh and Haman more palpable.
According to Rav Dovid Feinstein, this immediacy of the next party would pique Achashverosh’s curiosity, and keep him in suspense. Besides this, it is important to remember that the Jews were already fasting for two straight days, and Esther had asked the Jews to fast for three days, culminating in the next day. The merit of their fasting will both spiritually and psychologically support Esther’s efforts at that day’s feast.
According to R’ Meir Arama, pushing the next party into the next day was Esther’s attempt to stall her inevitable request from the king. Without a clear sign from H-Shem, she was confused if she should fight Amalek using Yaakov’s method, or Moshe’s. Yaakov (Bireishis 32:9) attempted to defeat Eisav, Amalek’s ancestor, through gifts. Moshe (Shemos 17:8-13) utilized prayer and war against the nation of Amalek.
The Yalkut Shimoni (1056) writes that Amalek is defeated machar, tomorrow. This is because Moshe, at the first national encounter against Amalek, said “tomorrow I will stand on top of the mountain” (Shemos 17:9).
The Maharal explains that Amalek does not recognize an other, a tomorrow. Amalek causes religious doubt (the Hebrew word safek has the same gematria as Amalek.) by forcing the brain to consider only one approach to a Torah dilemma; if that approach does not work, there can be no other way to look at the topic.
Perhaps another reason why the next day was so critical to Esther’s plan can be gleaned from the gematria of the Hebrew word machar, (“tomorrow”) (40+8+200=248). This is the same number as the positive commandments (Makkos 23b-24a), which themselves correspond to the major bones and sinews in a man1. Therefore, one more day of the Jews performing positive mitzvos and teshuva will help Esther. Perhaps this is the reason why the Midrash later notes that Haman was advised to approach Achashverosh specifically baboker (“in the morning”) (Esther 5:14), which the Midrash says is the time of reading the Shema.
1The significance of this number is also the reason for adding three words to the twice daily recitation of the Shema, which would only have 245 words alone (see Shulchan Aruch Orach Chaim 61:3 and Mishnah Berurah 61:6).