Musar su Ester 4:16

The rehabilitation also required two instruments i.e. Mordechai and Esther. Mordechai symbolised atonement for the sin, by refusing to bow to Haman's image, symbolised atonement for the sin of idol worship; Esther, by frightening Israel who were watching her inviting their arch-enemy to a feast with her husband-king, expiated the sin of partaking of forbidden food and enjoying it. Our sages (Megillah 15) cite several reasons why Esther did this, Rabbi Nechemyah saying that she wanted the Jews to do תשובה, repentance. The Jews did not turn to G–d and repent as long as they felt that a Jewish queen would protect their political interests. Esther wanted the fear generated among the Jewish people by her invitation of Haman to the meal to foster feelings of penitence amongst them. This is why she demanded that Mordechai decree a three-day fast for all the Jews of Shushan and asked that they assemble i.e. pray in their synagogues. The word כנוס, assemble, was the opposite of the characterisation of the Jews Haman had used when he described them to the king as מפוזר ומפורד, "scattered and dispersed." Haman counted on the dispersal and fragmentation of the Jewish people to help him defeat them.

For this reason one must read the Megillah word for word slowly. For every word and letter possesses sanctity and harbors esoteric secrets. It is also worthwhile mentioning the merits of Mordechai and Esther with intent because they sacrificed themselves on Israel’s behalf with their cries and prayers. Esther also sacrificed herself by going in to Achashveirosh, as she herself declared, “And if I am lost, I am lost” (Esther 4:16).