Musar su Ester 4:1

The sin the Jews committed with their bodies at that time was their free-will participation in the feast Ahasverus had prepared in Shushan. The two sins combined were of sufficient gravity to prompt G–d to bring about the decree of Haman to wipe out all the Jews. Rashi spells this out in his commentary on Esther 4,1 "Mordechai knew all that had taken place." He was shown in a dream that Haman's decree enjoyed Heavenly approval. We are told in Megillah 12 that Rabbi Shimon bar Yochai's students asked him why the Jews during the time of Mordechai had all become guilty of death. The Rabbi suggested to the students that they themselves should come up with the answer. The students attributed the decree to the Jews having enjoyed the feast to which Ahasverus had invited them. Their teacher immediately demurred saying that if this were so only the Jews of Shushan would have been guilty! Thereupon the students asked Rabbi Shimon to provide the answer. He told them that it was because they had prostrated themselves to the idol. The students wanted to know if an obeisance which was only for show carried such a severe penalty? Rabbi Shimon told them that just as the Jews had not really worshipped that idol in their hearts so G–d had not really intended for them to be annihilated. The author of Manot Halevi writes in his introduction that we can learn from the principle espoused by Rabbi Shimon bar Yochai that the decree was indeed due to the two sins committed by the Jewish people, but that there is a difference between decrees which have been sealed with a seal of blood and those which have been sealed with a seal of clay. The question had also arisen as to which of the two sins had brought about the sealing of the decree.

This is the meaning of the verse, “And Mordechai knew” (Esther 4:1). That is, he knew the essence of the matter — that the decree had been issued on account of the great harm they had done to the Shechinah when they benefited from the feast of that evildoer. Therefore it states, “And Mordechai donned sackcloth and ashes and cried out with a great and bitter cry.” “And he donned sackcloth” — This was to atone for the sin and to weaken the power of the “four hundred men” who accompanied Eisav when he came to meet his brother Yaakov. For it is stated concerning this event, “And Yaakov was very afraid” (Bereishis 32:8). That is, he was afraid of the four hundred impure husks and destroyers that accompanied Eisav. This is why Mordechai donned sackcloth, because the numerical value of the word “sackcloth” [שׂק] is 400. Thus his intention was to weaken the power of the wicked Eisav. Then Mordechai informed also Esther of the great harm that had been done at the feast of Achashveirosh. Therefore it states immediately after this, “And Esther donned ‘kingship’” (Esther 5:1). That is, she donned the spirit of prophecy (Megillah 14b). Esther then proposed that they fast for three days and three nights in order to counteract the filth that Haman and Achashveirosh had injected into them by means of their feast. In this way the power of the filth that had sullied them through that eating and drinking would be enfeebled, for it was weakened through their fasting, thereby enabling the collective soul of Israel to shine as before.