R’ Joseph Pearlman writes that the verse uses the active verb “to kill” instead of the more passive, “to be killed” because it was anyone’s responsibility to kill the transgressor. Anyone who approached the king would automatically become Public Enemy #1, and would be liable to death at the hands of anyone eager to show one’s patriotism and fealty to the king.
10. And the king removed his ring from his hand and gave it to Haman son of Hamdasa the Aggagite, enemy of the Yehudim.
According to M’nos HaLevi, the significance of Achashverosh giving Haman his ring is a sign that he consents to an agreement with Haman.
The Midrash here (Esther Rabbah 7:20) that Achashverosh hates the Jews more than Haman. After all, “the custom of the world is for the buyer to give a pledge to the seller. But here, the seller [Achashverosh] is giving the pledge [the ring].”
The Alshich writes therefore, that this giving of the ring is a legal transaction indicating an acceptance of Haman’s offer, an amount Haman is not likely to be carrying with him.
The Megillas Sesarim writes the ring means Achashverosh is giving Haman full authority to do anything he likes.
The Talmud (Megillah 14a) writes that the removal of the ring was stronger than forty prophets and seven prophetesses. None of them could encourage the Jews to repent as much as this one act. The Jews seemingly do not repent en mass until their very survival is threatened. R’ Mendel Weinbach says that this act is particularly frightening for the Jews because they know Achashverosh is capricious, and is famous for changing his mind. Once he gives authority to Haman, though, the Jews realize that they are in serious danger.
The Bircas Chaim asks why, when Mordechai is elevated to Haman’s position (Esther 8:2), does Achashverosh immediately give Mordechai his ring? In contrast with Mordechai at that point, Achashverosh does not trust Haman. However, now that Haman is willing to give this great amount of silver to the government, Achashverosh is under the mistaken impression that he is patriotic.
In Pachad Yitzchak, Rav Yitzchak Hutner wonders why the Talmud calls this incident the “removal of the ring” when it is Haman’s desire to kill the Jews which should be the focus. In response, he writes that whenever the descendants of Eisav or Yaakov prosper, the descendants of the other fall (see Rashi to Bereishis 25:23). Therefore, Achashverosh’s raising up of Haman necessitates a corresponding lessening of the Jews in the esteem of the king.
There are numerous reasons given for Bigsan and Seresh’s anger. The Yalkut Shimoni (1053) says that Bigsan and Seresh previously had important positions, and were upset with Mordechai for seemingly usurping them. The Malbim sees this in the actual words of the verse. After all, the verse relates Mordechai’s “sitting at the king’s gate” to Bigsan and Seresh’s anger to point out that their anger was directly caused by his position.
The Talmud (Megillah 13b) says they were upset with the king and queen because they were tired at nights having to protect their door as they spent time together, much like Pharoah became upset with the baker and butler for small reasons (Bireishis 40:1).
Rav Elisha Gallico says they were upset that Mordechai was sitting at the king’s gate, deciding cases based on Jewish law. Bigsan and Seresh therefore saw it as a patriotic duty to kill the king (who was, by the way, not Persian) for his seeming betrayal of Persian law in promoting a Jew to this position.
The Me’am Loez writes that the two of them were relatives of Vashti, and waited this long period of time to avenge her death. Another opinion he brings is that they were upset that Achashverosh rejected Haman’s daughter during the search for a new queen, and Haman convinced them to join in a rebellion against the king. The Me’am Loez also quotes Yossipon that this was just one part of a much larger rebellion, and that these two wanted to kill Achashverosh to bring the king’s head to the Greeks, enemies of the Persians, and thereby ingratiate themselves to them.
The Malbim points out that, regardless of the reason, their motivation was petty. This parallels the story of Yosef mentioned in the above Talmud. The Malbim continues that, just as H-Shem can inspire a king (Pharoah) to be angry with his servants for no reason, so, too, can H-Shem inspire a servant (Bigsan and Seresh) to hate a king for no reason. Rav Dovid Feinstein asks why these two stories are being paralleled by the Talmud. He answers that the verse says “shnei” (“both”), equating the feelings of Bigsan and Seresh. In the natural order of things, this is impossible because no two people can have the same exact emotion from the same exact motivation in the same exact degree. This is yet one more indication that these events were led Divinely.