The Haggadah quotes the Mishnah (Berakhos 12b) that discusses the recitation of the final paragraph of the Shema that includes a remembrance of the Exodus from Egypt:
R. Elazar Ben Azariah said: Behold I am like one who is seventy years old, and I have never been worthy to understand why the Exodus from Egypt should be mentioned at nighttime until Ben Zoma expounded it: for it says: "So that you may remember the day of your departure from the land of Egypt all the days of your life" (Deut. 16:3). [Had the text said,] "the days of your life" it would have meant [only] the days; but "all the days of your life" includes the nights as well. The Sages, however, say: "the days of your life" refers to this world; "all the days of your life" is to add the days of the messiah.The Gemara adds:
It has been taught: Ben Zoma said to the Sages: Will the Exodus from Egypt be mentioned in the days of the messiah? Was it not long ago said: "Therefore behold the days come, says the Lord, that they shall no more say: 'As the Lord lives that brought up the children of Israel out of the land of Egypt'; but, 'As the Lord lives that brought up and that led the seed of the house of Israel out of the north country and from all the countries where I had driven them'?" (Jer. 23:7-8). They replied: This does not mean that the mention of the Exodus from Egypt shall be obliterated, but that the [deliverance from] subjection to the other kingdoms shall take the first place and the Exodus from Egypt shall become secondary.The implications from this familiar passage is huge. It seems that according to R. Elazar Ben Azariah and Ben Zoma the commandment to remember the Exodus from Egypt will not apply in the Messianic Era. The commandment only applies during the days and nights of the pre-Messianic Era. But once the messiah comes, we will remember that final redemption and not the redemption from Egypt (as implied by Jeremiah). In other words, the biblical commandment to remember the Exodus from Egypt will no longer apply and is not eternal. Furthermore, there are other commandments that are intended to remind us of the Exodus from Egypt. The full biblical passage quoted in the Mishnah is:
Therefore you shall sacrifice the passover to the Lord your God, from the flock and the herd, in the place where the Lord chooses to put His name. You shall eat no leavened bread with it; seven days you shall eat unleavened bread with it, that is, the bread of affliction--for you came out of the land of Egypt in haste--that you may remember the day in which you came out of the land of Egypt all the days of your life. (Deut. 16:2-3)The commandments to bring the Passover sacrifice and to eat matzah are both explicitly linked to remembering the Exodus from Egypt. "Le-ma'an tizkor es yom tzeiskha me-Eretz Mitzrayim kol yemei hayekha--that you may remember the day in which you came out of the land of Egypt all the days of your life" also applies to those two commandments, and therefore any limitations on remembering the Exodus from Egypt should also apply to those two commandments. Therefore, according to R. Elazar Ben Azariah and Ben Zoma, they should not apply in the Messianic Era. This seems to contradict the principle of the eternity of the Torah.
The Rashba, in his Aggadic commentary to the Gemara in Berakhos, explains that the "le-ma'an" in the above verse is not giving a reason for the commandments but describing a secondary element of the commandments. In order to properly bring the Passover sacrifice and eat matzah, one must remember the Exodus from Egypt (cf. similar language in Ex. 23:12). The Maharal (Tiferes Yisrael, ch. 52) suggests that "le-ma'an" implies a necessary outcome and not a reason. Only if one eats matzah is one able to properly remember the Exodus from Egypt. However, the remembrance is not a part of the commandment to eat matzah (cf. Deut. 29:18). According to both of these explanations of the verses, neither the commandment to eat the Passover sacrifice nor the commandment to eat matzah will be nullified in the Messianic Era, even according to Ben Zoma. See also the translation of R. Saadia Gaon and Seforno's commentary to Deut. 16:3.
The Rashba also addresses the issue of the nullification of the commandment to remember the Exodus from Egypt. How can a commandment be nullified, even if only in the Messianic Era? The Rashba explains that the main point of the commandment is to instill in our hearts that God guides the world and is omnipotent, and to lead us to complete trust (bitahon). Therefore, this point will also be in effect in the Messianic Era when we remember the final redemption instead of the Exodus from Egypt, and will even be more powerful because those miracles will be greater than in Egypt.
This explanation is cited widely--see, for example, Derashos R. Yehoshua Ibn Shuaib, first day of Passover; R. Ya'akov Ibn Haviv, Ha-Kosev, Ein Ya'akov, Berakhos 12b; R. Yaa'kov Zvi Mecklenburg, Ha-Kesav Ve-Ha-Kabbalah, Deut. 16:3; R. Zvi Hirsch Chajes, Toras Nevi'im, Hukas Olam p. 75. However, it is very difficult to understand. It seems that according to the Rashba, the essence of the commandment will remain the same but the form will change. Is that not a change in a Torah commandment? The Yefeh To'ar (Vayikra Rabbah 13:3, unabridged) writes, "In my humble opinion, [the Rashba's] answers are weak and can be challenged."
R. Shlomo Wahrman, Oros Ha-Pesah ch. 45, offers a different explanation. In this pre-Messianic Era, we praise God for specific redemptions. However, in the Messianic Era our praises will be for all of the redemptions. According to Ben Zoma, in the Messianic Era the remembrance of the Exodus from Egypt will incorporate a remembrance from other troubles, including the final messianic redemption. According to the Sages, however, the remembrance of the Exodus from Egypt will remain solitary and other praises will be recited separately. However, this still means that, according to Ben Zoma, there will be an addition to the commandment which is also contrary to the principle of the eternity of the Torah.
The Maharal (ibid.) has a very different approach to this matter. He suggests that Ben Zoma and the Sages agree on matters of practice--they all agree that the remembrance of the Exodus from Egypt will apply in the Messianic Era. However, according to Ben Zoma the commandment is to remember the formation of the nation of Israel, which will always be the Exodus from Egypt. Therefore, the commandment will certainly apply in the Messianic Era and does not need to be extended by the verse. However, according to the Sages the commandment is to remember the good that God does for our nation. Therefore, the Sages need an explicit extension in the verse. But according to all the commandment applies even in the Messianic Era.
The Yefeh To'ar (ibid.) has a different approach. He states the commandment to remember the Exodus from Egypt is merely to remember it in our hearts and not to say it out loud. Therefore, the whole debate in the Mishnah between Ben Zoma and the Sages is about a rabbinic commandment, with the biblical verse being only a mnemonic attachment (asmakhta). That the recitation of the final paragraph of Shema, the subject of this whole debate, is a rabbinic commandment, see Magen Avraham 69:1; Sha'arei Teshuvah, ad loc. 1; Rashba, Novellae to Berakhos 2a; Sha'agas Aryeh, no. 9; and elsewhere.