Even though this tremendous benefit of leaving slavery belongs before matzah and the Korban Pesach, since the slavery came first, nevertheless we explain the remembrance of marror only after we've first made remembrance of matzah and the Korban Pesach to show that the main benefit of Yetziat Mitzrayim is the essence of geula itself – that is, the acquisition that Hakadosh Baruch Hu made with us to be His people – and not just the cancellation of slavery and the departure from Egypt.
This means that if we had started with marror, it would imply that the great miracle was that we left the slavery of exile – that nations no longer embitter our lives! – but that's not the reality, because they still continue to fire mortars and Qassam rockets at us, etc. – from this exile we haven't been redeemed yet and won't be redeemed until Mashiach comes! But from the galut where we couldn't fulfill Mitzvot – from that exile we've already been redeemed, and therefore we specifically say the of "Pesach, matzah, and marror," as the redemption was about being able to fulfill the Mitzvah of Pesach properly!
It follows, then, that the moment Hakadosh Baruch Hu revealed Himself to Moshe Rabbeinu – on Rosh Chodesh Nisan – we were able to fulfill His Mitzvot. From physical slavery we were already redeemed on Rosh Hashanah (Rosh Hashanah 11a), but we only left our spiritual slavery on Rosh Chodesh Nisan. On that day Hakadosh Baruch Hu revealed Himself to Moshe Rabbeinu and said to him:
דַּבְּרוּ אֶל כָּל עֲדַת יִשְׂרָאֵל לֵאמֹר בֶּעָשֹׂר לַחֹדֶשׁ הַזֶּה וְיִקְ חוּ לָהֶם אִישׁ שֶׂה לְבֵית אָבֹת שֶׂה לַבָּיִת :
Speak to the entire congregation of Israel, saying: On the tenth of this month, let each man take a lamb for his father's house, a lamb for each household.
Rashi explains that Moshe was told to speak to them on that day, the first of Nisan, and tell them to take the lamb on the tenth of the month.
The Ba’al Haggadah teaches that the redemption of Egypt was fundamentally a redemption of the soul – the ability to fulfill Mitzvot. This raises the question: did that redemption begin already on Rosh Chodesh Nisan, when Bnei Yisrael were first commanded in Mitzvot, beginning with the Korban Pesach? This is the meaning of the question in the Haggadah:
י ָ כ ו ֹ ל מ ֵ ר ֹ א שׁ ח ֹ דֶ שׁ – One might think from Rosh Chodesh. The answer is no:
וֹם הַהוּא ּ תַּלְמוּד לוֹמַר בַּי – The Torah teaches: on that very day.
But then another possibility arises: perhaps the redemption occurred earlier that same day, since on the fourteenth of Nisan Bnei Yisrael were already circumcised. Chazal state that Bnei Yisrael was redeemed through two bloods – the blood of the Korban Pesach offering and the blood of circumcision, as it says:
חֲיִי ְ בְּ דָ מַ יִך ְ חֲיִי וָאֹמַ ר לָך ְ בְּ דָ מַ יִך ְ וָאֹמַ ר לָך – And I said to you, ‘In your blood you shall live,’ and I said to you, ‘In your blood you shall live.’ This is the intent of the Haggadah’s follow-up question:
יָכוֹל מִ בְּעוֹד יוֹם – One might think while it was still day.
The final answer is:
תַּלְמוּד לוֹמַר בַּעֲבוּר זֶה – The Torah teaches: for the sake of this, which the Haggadah explains as referring specifically to the moment when matzah and marror are placed before a person. Thus, although the process began earlier, the full realization of the redemption is tied to the night of the Seder – while its spiritual roots were already established on the morning of the fourteenth of Nisan.
We brought the words of Rashi in Parshat Shlach, who says that the eight threads of the tzitzit correspond to the eight days from when they left Egypt until they crossed Yam Suf. We asked – how can it be eight days, when it's only seven days from the 15th of Nisan? Rashi answers us in the name of Rabbi Moshe HaDarshan: at that very moment when Bnei Yisrael performed the Mitzvah of Brit Milah and the Mitzvah of Korban Pesach, they already had redemption of the soul – they were able to fulfill the Mitzvot of the Borei Olam, because they were no longer enslaved; for the entire burden of servitude existed only to prevent them from fulfilling the Mitzvot!
If so, we can now understand the yesod hidden here. The geula from Egypt is divided into two aspects. True, Hakadosh Baruch Hu is the one who redeemed us from Egypt. If so, why was the redemption from Egypt not eternal? The Kli Chemda tells us that it indeed was an eternal redemption, but from a spiritual perspective, not a physical one. Since we left after 210 years and were not there for the full 400 years, the redemption of the body was not completed. And when will it be completed? Through the other exiles: Galut Bavel, when Chananya, Mishael, and Azarya come and redeem us; Galut Madai, when Mordechai and Esther come and redeem us; Galut Yavan, when Mattityahu and his sons come and redeem us... until, B'ezrat Hashem, the Melech HaMashiach will come and redeem us, and then our geula will be complete and eternal, Amen v’Amen!!!