In the book 'Collection of Letters' by Rabbi Yaakov Meir Shechter shlit"a, in a letter written on the 28th of Sivan 5731 to R' Chaim Shlomo, Rabbi Shechter wonders about the severe dispute, "How do great and holy ones disagree with the true tzaddik in the aspect of Mashiach". 

Here are selected parts from the letter that reached us:

To the honorable and dear Yedid Nafshi, the esteemed tzaddik R' Chaim Shlomo and his peace be increased,

Regarding the matter of the holy tzaddikim who did not know of our holy Rebbe, and yet they were holy and awesome. And we too need to be careful not to damage our emunah (faith) in tzaddikim, in the faith in the tzaddik "wounded for our transgressions"[1] (Isaiah 53:5). This can cause, God forbid, a blemish in the emunah in the tzaddik in the aspect of Moshe himself. On the other hand, we see that there were simple people who did merit to be with the tzaddikim during the concealment.

And regarding the dispute of Korach and his assembly against Moshe and Aharon, it is told about the holy Rebbe, the author of 'Yismach Moshe' zy"a, who merited to remember all his reincarnations, and said he remembers the dispute of Moshe with Korach, and he was among those who did not want to get involved in this dispute. And it is possible that there were many smaller ones who recognized the truth. For we see that he succeeded in enticing 250 heads of Sanhedrin, while the simple people were with Moshe Rabbeinu.

And so, it is even with great and holy ones who do not fully know the tzaddik. In contrast, there are simple people who do know him, and the secret of this is hidden from us.

It is known that the Baal Shem Tov did not want to descend into this world until he was promised sixty mighty ones (see Avnei HaBarzel, Shabbat Kodesh 1, 531), and without this, he would have remained hidden in this world.

In any case, I have brought you several examples that there can be tzaddikim and holy ones and miracle workers who do not fully know the secret of Mashiach "wounded for our transgressions", and each time this secret was hidden in a completely different way. And see in the Zohar (Ki Teitzei page 282) that Rabbi Shimon bar Yochai asked Elijah the Prophet to reveal the faithful shepherd (Moshe Rabbeinu), because the Tannaim, masters of the Mishnah, do not know him and do not recognize him, and about him it is said "and he was wounded for our transgressions".

Letter from Rabbi Yaakov Meir Shechter for download 

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[1]  This is a verse in the Tanach (Isaiah 53:5) "But he was wounded for our transgressions, crushed for our iniquities; the punishment that brought us peace was on him, and by his wounds we are healed", and in the Gemara (Sanhedrin 98b) it is explained about Mashiach, that he suffers from ailments for the sake of the entire Israel. And see in Likutei Moharan (Siman 118) where it is written that every tzaddik of the generation also suffers afflictions for the sake of the entire Israel to ease their burden, for he is in the aspect of Mashiach.