ערך מקוה

As is explained elsewhere — the great stature of holy desire and will. And that one must be a great stubborn one [ikashan gadol] in the matter of holy will and desire. And then through all of this he will merit to be saved from transgression and from all manner of bringing things from potential to actuality that are not of holiness. And he will merit to draw close in truth to the true Tzadik — through whom he will bring all matters of holiness forth from potential to actuality in perfection as he wishes. Through immersions in the mikveh [ritual bath] all the enemies fall — and all the afflictions and obstacles that prevent a person from serving G-d are nullified. For through immersion in the mikveh one nullifies oneself to G-d in complete nullification — in the aspect of mesiras nefesh [self-sacrifice]. Which is the essential perfection of the holy will — that the will must be strong in the manner of mesiras nefesh. And this is the aspect of immersions in the mikveh. And therefore when one enters and is hidden within the water — and surrenders his soul to G-d and binds himself to Him, blessed be He, with the full strength of his desire and will toward holiness — and this is the essential intention of his immersion: that he merit to draw upon himself through this a new holy spirit [ruach chadash d'kedushah]. And then through this he is encompassed within the root of the supernal holy spirit — which is the aspect of the spirit of G-d [ru'ach Elokím] hovering over the face of the waters [Genesis 1:2]. And through this he merits to bring forth the new holy spirit from potential into actuality as above. And when this rises, that falls — and automatically all the enemies and the opponents are nullified and fall. Which are the essential obstructors from bringing matters of holiness from potential to actuality. And this is alluded to in the verse: "The hope [mikveh] of Israel — G-d — all who forsake You shall be shamed, and those who turn away in the land shall be inscribed. For they have forsaken the source of living waters, etc." [Jeremiah 17:13] — as explained in the inner teachings. (The following is from the translator, not from the original text.) This large grouping spans from the Zayin to the Mem of the Alef-Bais and contains some of the most practically urgently needed teachings:

The essential blemish of faith in the sages comes from those who dispute the truly wise sages — because they are wise in their own eyes in the futile wisdoms of this world, all of which are wisdoms of falsehood — since through these wisdoms one does not merit the true and eternal purpose. And in truth the root of all these wisdoms — whether the outright external wisdoms of the philosophical investigators, or the ordinary wisdoms of the world that are against the point of truth — all derive solely from the fact that their entire intention is only for the sake of the bodily desires. Which is the aspect of weekday eating [achilas chol], where the liver is nourished first and afterwards the brain. And through the holiness of the delight of Shabbos [oneg Shabbos] — when the brain is nourished first — through this — [through this] — all the aforementioned disputants are subdued, and the faith in the sages is repaired.

And this is alluded to in the verse: "The hope [mikveh] of Israel — G-d — all who forsake You shall be shamed, and those who turn away in the land shall be inscribed. For they have forsaken the source of living waters, etc." [Jeremiah 17:13] — as explained in the inner teachings.