How relatively important or non-important is the messianic idea in Judaism? In his reading of the participation of Nachmanides in the public dispute at Barcelona, Hyam Maccoby suggests not very much. The messiah is not “essential,” is not a fundamental, not an ikkar in Jewish tradition, because, according to Maccoby, Judaism is not bothered by the idea of an original sin that only a supernatural savior could redeem. As per Maccoby, the coming of the messiah for Nachmanides is something like a “reward” or “general hope.” Indeed, “if Jews explained their religion to non-Christian inquirers (to the King of the Khazars, for example, as in Judah Halevi’s Khuzari), they did not begin with the Messiah as an essential Jewish doctrine. There were other far more important matters to explain first, such as the Exodus from Egypt and the Covenant on Mount Sinai” (Judaism On Trial: Jewish-Christian Disputations in the Middle Ages, p.50). I’ll only add that what seemed to matter more to Nachmanides was eternal life in Gan Eden in the world to come.
The messianic idea in Judaism as it appears in this particular context has more to do with Christianity and to Christian-Jewish disputation than anything directly related to the Judaism, or to the Judaism of the rabbis, what Neusner calls “normative Judaism.” Even as he consciously bucked the traditional skepticism of the rabbis, there was something diminutive about the messianic idea as Nachmanides understood it himself.
I’m taking a quick look at two texts.  The Vikuach proports to be something like a transcript of the disputation with Friar Pablo Christia in 1263 about the messiah as based on rabbinic sources. Nachmanides puts the messianic idea in a strong bracket in his public confrontation before the royal power of a gentile king in this confrontation with the power of preaching friars to stir up trouble for Jews. Gentile political violence hovers over the argument.  For its part, the messianic idea in the Book of Redemption, which Nachmanides’ translator Charles Chavel links with the disputation, is more strange than a simple declaration of faith. I’ll cite more of it below; but as I’m cribbing the last lines of the final poem that concludes this little text, the messianic idea is a wistful waiting for the end of miracle and wonder.
The Vikuah of Nahmanides + Commentary to Deuteronomy
That man [Fray Paul] now stood up and said, ‘I shall bring another proof that the time of the Messiah has already passed.’ However, I spoke myself: ‘My lord King, hear me. The Messiah is not fundamental to our religion. Why, you are worth more to me than the Messiah! You are a king, and he is a king. You are a Gentile king, and he is a Jewish king; for the Messiah is only a king of flesh and blood like you. When I serve my Creator in your territory in exile and in affliction and servitude and reproach of the peoples who “reproach us continually”, my reward is great. For I am offering a sacrifice to God from my body, by which I shall be found more and more worthy of the life of the world to come. But when there will be a king of Israel of my religion ruling over all the peoples, and there will be no choice for me but to remain in the Jewish religion, my reward will not be so great. ::” No, the real point of difference between Jews and Christians lies in what you say about the fundamental matter of the deity; a doctrine which is distasteful indeed (Maccoby, p.119, emphasis added).
The lack of merit in the messianic era and the cardinal significance of the world to come are expressed here in this commentary to Deuteronomy 30:6:
“God, your Lord, shall circumcise your heart” (Deut. 30:6) [. . .] What I am going to say is borne out by Scripture. From the time of Creation, man could do as he pleased, [he could be] righteous or wicked. And so it has been for the entire Era of the Torah, so they can be awarded merit for choosing good, and punishment for willing evil. In the Days of the Messiah, however, the choice for good will come to them naturally, their heart will not crave what is inappropriate and shall not desire it at all. This is the circumcision mentioned here— covetousness and cravings are a foreskin to the heart, and circumcision of the heart means that it shall neither covet nor crave. At that time, man will once again be how he was before the sin of Adam, when he naturally did what he ought to do, and his will was not conflicted [. . .] This is what our Rabbis said (cf. Shabbat 151b): “ ‘Years will come about which you will say I have no desire in them’ (Eccl 12:1)—these are the Days of the Messiah, which have neither merits nor demerits.” For in the Days of the Messiah man will have no desire; he will do what he ought to do naturally. That is why they have neither merit nor demerit, because merit and demerit depend upon desire.
Book of Redemption
On one hand, even in the Book of Redemption, the messianic idea is not recognized as fundamental. Nachmanides writes, “most of Moses’ words are not intended to inform us of coming events.” But they do promise bounty and consolation. He writes this book for those who are/were weary of the exile (Gate 1). The Book of Redemption wanders around in gematria and verses. It has the character of puzzle, like Wordle.
Messianism is not an essential teaching (ikkar). The ultimate goal and “[o]ur reward and hope lie rather in the World to come, in the enjoyment of the soul in the Garden of Eden, and in being spared from the punishment of Gehenna.” For all that, the messianic idea holds out closeness to God, purity, sanctity, and vengeance against the enemy, the sanctification of God’s name in the face of the nations. The main logical line of argument is this: once promised, a prophecy proceeds from potential to the necessary and actual; no goodness once promised by God can be revoked by God (Gate 2).
Nachmanides deliberately goes against the words of the sages who cautioned against calculating the end, search for the end, lest the come up with a date and suffer a crisis of faith when that calculation does not pan out. But he feels confident enough. Reading through the book of Daniel, he calculates that the messiah will come in the year 1403 CE. Nachmanides explains that all of this is only plausible and possible. From his vantage point in the 13th century, the end is “distant” and “remote.” But we (his generation) are closer to the end than were the rabbis of the Talmud. Happy is he who waits outside the Land during the wars and bloodshed of the first Jewish messiah, the messiah son of Ephraim/Joseph. In the little poem at the end of the book glossed mostly from Daniel (also from Isaiah and Job), there is this peculiar formulation. Nachmanides hopes “by the multitude of [God’s] mercies” that we will see “the wonder and sign when ‘the end of the wonders will approach’” (Dan. 12:6) (Gate 4).
[translated by Charles Chavel]
Reflecting mostly off the Vikuach, Maccoby’s gloss is actually more substantive than what Nachmanides has to tell him. I’m including the gloss here not because I think it gets at Nachmanides as much as it speaks to a more general point made by Maccoby against making too much about the importance of the messianic idea in Judaism.
If, as Christians thought, the Messiah was divine, then his coming was for every human being the central and essential moment of all history, the moment that counted for every individual’s personal salvation. For the Jews, the Messiah had quite a different significance. The essential struggle for salvation lay elsewhere; the Messiah was merely the reward, signifying that the struggle had proved successful. The Messiah did not solve the human dilemma; on the contrary, the appearance of the Messiah would show that the dilemma had already been solved. In Jewish-Christian controversy, of course, the question of the Messiah had to be a central focus of discussion; but that was because the Messiah, or Christ, was so important to Christians, not because he was so important to Jews. If Jews explained their religion to non-Christian inquirers (to the King of the Khazars, for example, as in Judah Halevi’s Khuzari), they did not begin with the Messiah as an essential Jewish doctrine. There were other far more important matters to explain first, such as the Exodus from Egypt and the Covenant on Mount Sinai.
Nahmanides’ contention that the Messiah is not of overwhelming importance in Judaism was based on the standpoint of the Talmud, which gives no support to any dogmatic view about the Messiah. It gives such a wide range of views on the subject that it is almost impossible, in Judaism, to hold a view about the Messiah that is heretical. The upshot is that the doctrine simply affords a general hope that history is moving towards an era of peace and justice, and that the struggles towards this end will not prove in vain. The character of this hope is political and social, not soteriological in the individual sense. Medieval Jewish thinkers differed amicably about whether to include the doctrine of the Messiah among the essential principles of Judaism (Maimonides included it, but Albo and Crescas did not). When Nahmanides told King James that, for a Jew, life in the Exile might have more meaning than life under the Messiah, he was not indulging in posturing or paradox, but spelling out the saying of the Mishnah, ‘Better is one hour of repentance and good works in this world than the whole life of the world to come’ (M. Avot., 3: 17). In other words, there was more moral excellence in struggling towards a better world than in enjoying it once it had arrived.
This question…is intimately bound up with the status of the Messiah; for it is only if mankind is thought to be in a hopeless state of sin that a divine Messiah is needed to rescue mankind from an eternity of damnation. In Judaism, Nahmanides stoutly maintained, there is no doctrine of Original Sin, in the Christian sense that Adam’s guilt was inherited by his posterity…It was true, however, that mankind as a whole inherited the evil consequences of Adam’s sin, namely, the curse of work and the curse of pain in childbirth; this is all that we can conclude from the Scriptural account. Consequently, mankind does not stand in fear of eternal damnation because of the sin of Adam, which has been sufficiently atoned for. There is thus no need for a divine Saviour to rescue mankind from a devil-dominated earth. Here again, the Jewish Messiah occupies a far smaller place in the scheme of things, being a reward, not a necessity.
[Hyam Macoby, Judaism on Trial, pp.50-52]