The Malbim explains Haman’s advisers’ words as implying that since Haman started falling already in his degrading display of honor to Mordechai, the natural inertia will cause him to continue to fall.
The Talmud (Megillah 16a) interprets the verse’s double language of “nafol tipol” (“falling you will fall”) by noting that the Jewish people are compared both to the dust, and to stars. The Maharal asks on this Talmudic statement that, historically, every nation has ups and downs. When Babylonia, Greece, Rome, or any other nation sinned, H-Shem caused their civilizations to decline. He answers that the difference for the Jews is that H-Shem directly supervises their ascents and downfalls. Therefore the practical difference is how far up or down.
The Midrash (Bireishis Rabba 8) on Bireishis (1:28) says that man can fall to the lowest depths. There is no middle ground for the Jews; they either fall into the dust or rise to the stars.
R’ Yehonason Eibshutz quotes the Talmud (Brachos 4b) that there is a principle that H-Shem saves the Jews when they are at their lowest. H-Shem waits (kaviyachal, as it were) for the individual Jew or the nation to reach the dust, the lowest point. If a person sitting on the floor falls, that person may fall to the floor. But when one is sitting on the floor and falls, there is not place further to fall. It is at that point that H-Shem must raise that person to the stars.
The Ben Ish Chai writes that the advisers pointed out to Haman that he himself said (Esther 6:11) that the honor received by Mordechai “ye’aseh” (“will be”) in the future tense. He thereby unwittingly cursed himself with Mordechai’s future success.
The Ginzei HaMelech quotes the Ta’amei Esther, who quotes the M’nos HaLevi, who in turn quotes R’ Eliezer of Garmiza that the words nafol tipol are written complete, both with vuvs because Mordechai’s six (the gematria of vuv) actions including fasting, walking through the streets, crying, etc (Esther 4:1) parallel the six (the gematria of vuv) forms of suffering endured by Israel (Esther 4:3). Therefore, Nafol Mordechai and tipol the Jews. The Ginzei HaMelech explains by quoting a Midrash (Vayikra Rabba 34:8) that Moshe accepted upon himself the pain meant for others, and Mordechai did the same. Therefore, paining these kinds of leaders pains all of the Jews. By doing that, Haman is pinning himself against the combined power of the entire Jewish nation.
In a more Kabbalistic explanation, the Rema writes that this falling is actually the second fall, as in the days of Adam (Bireishis 3:15), when the Yeitzer HaRa fell the first time.
The Sha’aris Yosef quotes the Nachal Kedumim that Mordechai was a gilgul, reincarnation, of Yaakov, and Haman was a gilgul of Eisav. One of his proofs for this idea is that the verse (Bireishis 32:12) in which Yaakov prays for Heavenly assistance against Eisav, he says, “hatzileini na miyad” (“save me please from the hand”), which have initial letters that spell out Haman. Although Yaakov never physically fought Eisav, he did fight Eisav’s guardian angel. The verses describing this exchange (Bireishis 32:25-30) never explicitly names the victor, which prompts the Midrash (Bireishis Rabba 77:3) to state that it would remain unclear who won except for the fact Eisav’s guardian angel had to go back and forth several times. Just as Eisav’s angel had to go back down, Haman’s advisers here are implying that, being a gilgul, Haman would similarly fall twice before Mordechai.
Haman called out his announcement that such shall be done for the man whom the king wishes to honor in the future tense. The easiest explanation may be that Achashverosh is rewarding Mordechai because he wants people to protect him in the case of future assassination plots. He is basically advertising, “You, too, can get this reward for protecting the king,” which is a statement which should logically be said in the future tense.
The Yalkut Gershoni quotes the Talmud (Bava Basra 12b) that since the ability to have prophecy no longer exists, prophetic insights have been given to fools, since people do not take them seriously. Haman was unwittingly saying that the reward they were all witnessing was indicative of Mordechai’s actual reward, which we will (iy”H) see in Esther 8:16.
According to Rashi, the word, “kazos” (“like the time”) is in the future tense. Accordingly, Mordechai is reminding Esther that there is no surety in her remaining queen in the future. For all she knows, Achashverosh will get rid of her in the same way he got rid of the last queen. If that would be the case, her effectiveness in defending the Jews has a potential expiration date.
According to Ibn Ezra, Mordechai is emphasizing to Esther that this very occasion is the reason why she is in the royal position in which she finds herself.
The Ohel Moshe writes that we are all here for one moment, to act in a way that will glorify H-Shem. We are all Divinely placed in the positions in which we find ourselves for a reason – whether we understand that reason, or not.
R’ Dovid Feinstein writes that Jews in prominent positions should realize that they are only there to make a Kiddush H-Shem.
Along the same lines, Vilna Gaon writes that Mordechai is telling Esther that her refusal will not just forfeit a reward, but will also be punished for being responsible for the deaths of the Jews.
The Malbim writes that H-Shem always has a set time to rescue the Jews, and Mordechai is telling Esther that this is the time to join in the rescue.
According to the Me’am Loez, Mordechai is pointing out that the Jews living in Persia might despair over time, and lose faith in their redemption.
Another opinion he brings is that this matter is time-sensitive, as Achashverosh may not have time to send messengers to recall the decree over his giant kingdom. G-d Willing, we will see in the final chapters of Megillas Esther that this concern was legitimate.
In regard to the Song at the Sea, Rashi on Shemos (15:1) teaches that a letter “yud” in front of a verb indicates the intent of the subject. In the Sfas Emes’s understanding of this verse, Mordechai’s actions indicate that he would not bow. It was an impossibility for him, so remotely distant from his normative code and conduct. The Chofetz Chaim teaches that this, too, teaches the important of avoiding compromising morals.
The Sfas Emes also teaches that this verse is prophetically promising that, in every generation, there will be someone who will not bow. Jews have and always will have at least one person who keeps to what is true. Ultimately, this is going to be Moshiach, may he come soon.