Examine the statement in Etz Chaim, Shaar Hanekudot, Shaar 8, ch. 6,

עַיֵּין עֵץ חַיִּים שַׁעַר הַנְּקוּדּוֹת שַׁעַר ח' פֶּרֶק ו',

that there can be no “turning of face to face” except through mitzvot requiring action.

שֶׁאֵין הַחֲזָרַת פָּנִים בְּפָנִים כִּי אִם עַל־יְדֵי מִצְוֹת מַעֲשִׂיּוֹת דַּוְקָא.

The text cited had previously discussed the stage of creation at which (i) the bracket of six sefirot known collectively as za (z’eyr anpin) and (ii) the sefirah of malchut1 were first emanated and revealed (in the World of Atzilut) from chochmah and binah, their spiritual parents. Adam had not yet been created, and hence, the avodah of fulfilling mitzvot did not yet exist. At this stage, if za and malchut had united “face to face,” there would be an effusion of Divine energy from the innermost aspect of za to the innermost aspect of malchut. This, however, would enable the kelipot to receive more than their due share of life-giving influence from the source of holiness. The union was therefore merely “back to back,” i.e., only the external aspect of za was drawn down to malchut.

Only after Adam was created and performed mitzvot, effectively “trimming and hacking off the thorns,” i.e., limiting the nurture of kelipot, could za and malchut be united “face to face.”

In other words, Divinity can be revealed within this world (without any nurture being illegitimately diverted to the kelipot) only by means of mitzvot whose performance entails an actual deed.

The reason for this, as given there in Etz Chaim,

וְטַעַם הַדָּבָר,

is that by means of good deeds, one brings about a supernal union, causing za and malchut to turn “face to face.”

כִּי עַל־יְדֵי מַעֲשִׂים טוֹבִים גּוֹרֵם זִיוּוּג הָעֶלְיוֹן וְכוּ'.

Now, why only mitzvot involving action?

וּלְהָבִין, אַמַּאי "מַעֲשִׂיּוֹת" דַּוְקָא?

Why can the same result not be brought about by mitzvot fulfilled by thought and speech?

This may be understood in the light of what is written in [Etz Chaim,] Shaar Man Umad,2

יוּבַן מִמַּה שֶּׁכָּתוּב בְּשַׁעַר מַ"ן וּמ"ד,

that first, before the supernal union takes place, there must be an elevation of mayin nukvin (i.e., an arousal initiated by the recipient) from the nukva (i.e., the feminine element) of za, viz., malchut,

כִּי צָרִיךְ תְּחִלָּה לְהַעֲלוֹת "מַיִּין נוּקְבִין דְּנוּקְבָא דִזְעֵיר אַנְפִּין",

and the mayin nukvin of nukva is the state of action, as explained there, in ch. 1.

וּ"מַיִּין נוּקְבִין דְּנוּקְבָא" הֵן בְּחִינַת עֲשִׂיָּה, כְּמוֹ שֶׁכָּתוּב שָׁם פֶּרֶק א'.

In other words: The things of this world, whose source is the sefirah of malchut (which is the nukva of za) must be elevated to their source in holiness. This can be accomplished only through mitzvot whose fulfillment requires actions performed with the material components of the world. This alone makes possible the supernal union which reveals Divinity within this world.

However, how can it be ensured that no part of this revelation will leak to the kelipot (which are also known as chitzonim—lit., “extraneous forces”)?

Good deeds are described as trimming and hacking off the thistles that attach themselves to the hinderpart,

וְהִנֵּה, הַמַּעֲשִׂים טוֹבִים נִקְרָאִים "כִּסּוּחַ וְקִיצּוּץ הַקּוֹצִים", הַנֶּאֱחָזִים בַּאֲחוֹרַיִים,

which is the state of deed,

שֶׁהֵן בְּחִינַת עֲשִׂיָּה,

as is written in [Etz Chaim,] Shaar 47, ch. 5.

כְּמוֹ שֶׁכָּתוּב בְּשַׁעַר מ"ז פֶּרֶק ה',

It is the performance of specifically these commandments that hacks away the kelipot which, like the unchecked roots of thistles or weeds in a vineyard, would otherwise encroach on the life-giving waters and divert them from their intended destination.

This [pruning is effected] by elevating the element of good that is concealed in them (i.e., in things of this world that are related to Asiyah) and that is enclothed in mitzvot of action,

וְהַיְינוּ עַל־יְדֵי הַעֲלָאַת הַטּוֹב הַגָּנוּז בָּהֶם הַמְלוּבָּשׁ בְּמִצְוֹת מַעֲשִׂיּוֹת

[elevating this element of good] to its source, to the sanctity of Atzilut that has already been refined.

לִמְקוֹרוֹ, לִקְדוּשַּׁת הָאֲצִילוּת שֶׁכְּבָר הוּבְרְרָה.

The performance of practical mitzvot thus makes possible the purification and elevation of those physical things that are in need of this by extracting the element of good that is within them and elevating it to holiness.

As to the statement there that Adam effected rectification (tikkun) through prayer as well, which would not appear to be a mitzvah requiring action,

וּמַה שֶּׁכָּתוּב שָׁם שֶׁאָדָם הָרִאשׁוֹן תִּיקֵּן גַּם כֵּן עַל־יְדֵי תְּפִלָּה,

this means [that he did so] through uttering the letters of Speech, i.e., not through the intent of prayer but by the actual deed involved, for the movement of one’s lips is also deemed a deed.3

הַיְינוּ עַל־יְדֵי אוֹתִיּוֹת הַדִּבּוּר, דַּ"עֲקִימַת שְׂפָתָיו הַוֵי מַעֲשֶׂה",

For they—these utterances—derive from the vivifying soul which is in one’s body and blood, whose root (and life-force) is in [kelipat] nogah.

כִּי הֵן מִנֶּפֶשׁ הַחִיּוּנִית שֶׁבַּגּוּף וְדָמוֹ אֲשֶׁר שָׁרְשָׁן מִנּוֹגַהּ.

As the Alter Rebbe explains in the Tanya, Part I, ch. 37, one’s G‑dly soul is incapable of uttering the words of Torah or prayer (which have to be sounded with the physical mouth, tongue, and teeth), except through the agency of the vivifying soul that is invested in the body.

We see from the above that uttering the words of prayer can also elevate mayin nukvin from the nukva of Asiyah, just as is done by the practical mitzvot.

The acts of refinement of Asiyah that are accomplished through practical mitzvot ascend to Yetzirah by means of the Divine Name Ban and from Yetzirah to Beriah and Atzilut, as noted in Shaar Man, Derush 11, sec. 7.

וְהִנֵּה, הַבֵּירוּרִים דַּעֲשִׂיָּה עוֹלִין לִיצִירָה עַל יְדֵי שֵׁם בַּ"ן, וּמִיצִירָה לִבְרִיאָה וְלַאֲצִילוּת, כְּמוֹ שֶׁכָּתוּב בְּשַׁעַר מַ"ן דְּרוּשׁ י"א סִימָן ז'.

Thus, we can understand why mere thought accomplishes nothing, as Essay 1 of Kuntres Acharon quotes above from the Zohar,

וּבָזֶה יוּבַן דְּהִרְהוּר לָא עָבִיד מִידֵי,

for unless mayin nukvin is elevated from the “kings of nogah,”4 it is impossible to draw forth drops from above to effect the union of zu’n, an acronym for the above terms za and nukva.

כִּי בְּלִי הַעֲלָאַת "מַיִּין נוּקְבִין" מֵהַ"מְּלָכִים" שֶׁבְּ"נוֹגַהּ", אִי אֶפְשָׁר לְהַמְשִׁיךְ טִיפִּין מִלְמַעְלָה לְזִוּוּג זְעֵיר אַנְפִּין וְנוּקְבָא,

This elevation can be effected only through activity on the level of Asiyah, as stated above.

Za and malchut can unite only if a degree of illumination that transcends them both is drawn down upon them. To use a mortal analogy: Concerning the union of man and woman, it is written, “Male and female did He create them, and G‑d blessed them and said to them, ‘Be fruitful and multiply.’”5 I.e., in order for their union to bear fruit, a blessing must first descend upon the partners from above. And these “drops” of blessing from a source in Divinity that transcends both za and malchut cannot be drawn forth unless mayin nukvin is aroused and elevated by the refinement of the materiality of kelipat nogah.

For [za] desires to seek its nurture from its “mother,” i.e., from the sefirah of binah, rather than giving forth for the lower realms,

כִּי רוֹצֶה לִינַק מֵאִמּוֹ וְלֹא לְהַשְׁפִּיעַ לְמַטָּה,

It is only through the elevation of mayin nukvin of nogah that a higher degree of illumination is drawn down within za, causing it to desire to unite with the sefirah beneath it, viz., malchut.

as is written in [Etz Chaim,] Shaar Man, Derush 2.

כְּמוֹ שֶׁכָּתוּב בְּשַׁעַר מַ"ן דְּרוּשׁ ב'.

Examine Zohar, Parashat Pekudei, p. 244b, which states that there is a mode…of gazing….

וְעַיֵּין זֹהַר פָּרָשַׁת פְּקוּדֵי דַּף רמ"ד עַמּוּד ב': דְּאִית סִדּוּרָא כוּ' לְאִסְתַּכְּלָא כוּ',

Just as there is a mode of verbalized prayer, so is there a mode of prayer with kavanah by means of which one meditates and attains infinite heights, as one gazes upon the glory of the King.

This refers to the intentions (kavanot) in worship, and the supernal unions, for those who know and understand how to “gaze….”

וְהֵן כַּוָּונוֹת הַתְּפִלָּה וְיִחוּדִים עֶלְיוֹנִים לַיּוֹדְעִים וּמַשִּׂיגִים לְאִסְתַּכְּלָא כוּ',

Such individuals can have an impact on this world through their unarticulated intentions alone.

For their nefesh, ruach, and neshamah themselves constitute [the arousal initiated by the recipient which is known as] mayin nukvin, through their self-sacrificing devotion for the Torah,

כִּי נֶפֶשׁ־רוּחַ־נְשָׁמָה שֶׁלָּהֶם עַצְמָן הֵן "מַיִּין נוּקְבִין", בִּמְסִירַת נַפְשָׁם עַל הַתּוֹרָה,

and during the Tachanun prayer, during which we say “To You, G‑d, I lift my soul,” as is known.

וּבִנְפִילַת אַפַּיִם, כַּנּוֹדָע:

This ability, however, remains the province of a select few. The overwhelming majority of Jews accomplish this elevation through mitzvot of action involving an actual deed or speech. And in this manner, they are able to bring about a union “face to face” between za and malchut—the sublime union of Kudsha Brich Hu and His Shechinah, which draws Divinity down into this world.