Prologue:        It became a big Shabbos. But what was so significant about Shabbat HaGadol? The Taz (430) quotes R. Moshe Charif who explained that the reason for Shabbat HaGadol was to avoid confusion with the
splitting of the Yarden. Clearly the Mogen Avraham disagreed with this opinion for he does not cite it L'Halacha.  The question is why?

        Rav Moshe Feinstein ztl. explained (Darash Moshe II) that the key issue here is a reference to the power of a miracle. The Talmud (Shabbos 53) downplays those who need miracles performed for them in order to deal
with natural phenomena. A better means for dealing with the world is naturally, without relying upon the supernatural for Yeshua. 

        When it comes to Pesach, the same Amoraim who are against the reliance upon miracles, utilize the power of Nissim to highlight the Yetzias Mitzrayim (See Taanis, 25). The apparent difference between the
downplaying of Nissim for ourselves versus highlighting those for Pesach seems to be in the object receiving benefit from the extolling of the miracle. Hashem utilized the supernatural when creating and bringing about
Yetzias Mitzrayim in order to show the Jewish nation, the greatness of his power. However, after the exodus and subsequent Emunah in Hashem and Kabbalat Hatorah, proof to Bnei Yisroel of his greatness at the Yarden
should not have had to come about supernaturally. In the same way Hashem split the Yarden, he could have given the nation the means with which to build a bridge to cross the Yarden. He didn't. He felt that there was a
certain need to reaffirm the nation's Emunah. Hence, he split the Yarden. However, the act was not meant to be a "great" one. Hence, Rav Moshe notes that the Mogen Avraham could not include the splitting of the Yarden among the reasons that make this Shabbos great. 

        Miracles abound this time of year. But, unlike Chanukah and Purim, we do not mark these miracles with the same Berachot that we do when commemorating those occasions. This week's Chaburah focuses on that
Beracha.  It is entitled:

Ba Zman HaZeh: A Time for what?

        The Talmud (Berachos 54a) notes that one who sees a place where miracles happened to Bnei Yisroel, must recite a Beracha "She'asa Nissim l'Avoseinu B'makom Hazeh." Rav Achai Gaon (Sheiltos Vayishlach, 24)
expands this idea to include not only being in a place of miracles but even in a time of miracles. In that case, the proper Beracha would be "B'zman HaZeh" instead of B'makom Hazeh. We know that such a Beracha is
recited on Chanuka when lighting the candles and on Purim prior to the Mikra Megilla. Yet, the beracha is not recited on Pesach night during the Kiddush. Why recite the Beracha when performing these miracle-commemorating Mitzvot and not on Pesach (Pesachim 114b)? 

        The question is more compounded when we consider the Rosh chodesh Bentching. When we recite the  birkas Hachodesh, we highlight he who performs Nissim and associate those Nissim to Yetzias Mitzrayim (V'Gaal Osam Mei Avdus L'cheirus"). In the liturgy we associate Pesach-time with miracles so why not at the Seder? 

        When the Tur (473) discusses the issue, he explains that since a person mentions the miracles during the Maggid, he does not make a Beracha of She'asa Nissim. The Chida too (Machzik Beracha), feels that the reason we do not say She'Asa Nissim is because it recited in the Hagada.
        Older Girsaos seem to include a Beracha of She'Asa Nissim. Yet, the Beracha seems to have fallen out of use at least by the time of Machzor Vitri. Why?

        Moreover, the reasons not to recite the Beracha of She'Asa Nissim are not exactly parallel. The tur notes that the reason is that it will be recited later in the Hagaddah. He does mention where. The Sefer Yafeh
l'lev (VI) notes that when we recite L'Feechach and mention Nissim V'Niflaos, that is the reference to which the Tur refers. He does not mean to include She'Asa Nissim in the Beracha of Asher Gealanu. The Rokeiach,
Orchos Chaim and Kol Bo all seem to suggest that She'Asa Nissim is included in the Beracha of Asher Gealanu. However, the Mateh Moshe (619) says that it is the Tur's reference could be to any of the
references either Asher Gealanu or Lefeechach. According to him, there is no Machlokes as to why we don't say She'Asa Nissim in Kaddesh, we don't say it because it will be recited.

        The Aruch Hashulchan (473:2) adds that he does not understand why one should not recite a Beracha at the beginning and end of Hagadda the way we do at the beginning and end of Megilla? 

        The truth is that Rav Amram Gaon is cited by the Prisha (473:2) as being against the recitation of She'Asa Nissim on the grounds that Pesach night is a night of a greater message. Despite the bounds of Hakarat HaTov
for the Nissim that led to Yetziat Mitzrayim, Pesach night is a night of Yeshuya and should commemorate it without focusing on specific miracles. The Aruch HaShulchan explains that he does not understand this Peshat.

        However, perhaps one could suggest a different reason why She'Asa Nissim should not be recited on Seder night. The nature of Seder night is a Chiyuv of K"ilu Hu Yatza (ATA) MeMitzrayim. While one tries to recreate the Seder as if he were there, a mention of She'ASA Nissim l'avoteinu would uproot that image, limiting the Seder experience to something that happened in generations past.

Shabbat Shalom