What is the meaning of "va'Ya'avor Mordechai"?
Torah Temimah citing Megilah 15a #1: He'evir (he passed) the first day of Pesach in a Ta'anis (like Esther decreed). Torah Temimah - the three days were the 13th, 14th and 15th of Nisan. 1
Torah Temimah citing Megilah 15a #2: Avar (he crossed) a stream (to gather Jews to fast). Ya'aros Devash (2:9 DH v'Hinei) - i.e. he went from Shushan ha'Birah to join the Jews in Shushan itself, in Teshuvah and Tefilah.
Vilna Gaon: He transgressed Torah law. He fasted on Pesach, and did not eat Matzah and Maror 2 . The Midrash (Esther Rabah 8:7) says that [Mordechai said that they cannot fast on Pesach]. She replied, if there will be no Yehudim, there will be no Pesach! (He accepted this.) Also, she is queen, and he must accept her commands 3 - "k'Chol Asher Tzivesah Alav Esther."
Malbim: He passed in all streets of Jews and decreed the fast, like Esther commanded.
Ya'aros Devash (2:9): Fasting on Yom Tov is permitted mid'Oraisa, and sometimes even mid'Rabanan. It should have said that he transgressed the Torah obligation to eat Matzah! Really, he ate Matzah; refer to 4:16:5:2*. The Vilna Gaon (refer to 4:17:1:3) - 'he passed the first day of Pesach in a Ta'anis' teaches that he did not eat Matzah (PF). Aruch l'Ner (Yevamos 121b) - this opinion holds that they ate during the nights after the fasts (refer to 4:16:4:2 and the note there). Or, a k'Zayis was permitted; refer to 4:16:3:1.
The Torah Mitzvah to eat Maror is only with Korban Pesach! Perhaps he means that he transgressed even Torah law [and also mid'Rabanan laws]. (PF)
Even a Jewish king, we need not obey his command to transgress the Torah (Sanhedrin 49a)! Perhaps here he had to obey, for it was a Hora'as Sha'ah. (PF)
