Regarding the statement cited above: “The essence of the Shechinah was manifest in the lower realms” –וְהִנֵּה זֶה דְּעִיקַּר שְׁכִינָה בַּתַּחְתּוֹנִים הָיְתָה,
from the conceptual flow of the Midrash, it can be understood as implying that the term tachtonim, “lower realms,” refers to this physical world.מְבֹאָר מֵהַמִּדְרָשׁ דְּתַחְתּוֹנִים קָאֵי עַל עוֹלָם הַזֶּה הַגַּשְׁמִי,
At times, the term tachtonim can refer to the worlds of Beriah, Yetzirah, and Asiyah, which are “lower,” and of a different nature than Atzilus. (For as the Rebbe Rayatz explains in his maamar,1 Atzilus is entirely identified with G‑dliness, while the worlds of Beriah, Yetzirah, and Asiyah are characterized by independent existence.) More particularly, tachtonim is occasionally used to refer to the spiritual world of Asiyah which is lower, i.e., far less refined, than the worlds of Beriah and Yetzirah. Nevertheless, in this Midrash, the intent of the term is clearly this physical world.
For the Midrash proceeds to explain that because of the sin of the Tree of Knowledge, the Shechinah withdrew, ascending from the earth to heaven,וּכְמוֹ שֶׁמְּבָאֵר דְּעַל יְדֵי חֵטְא עֵץ הַדַּעַת נִסְתַּלְּקָה הַשְּׁכִינָה מֵאֶרֶץ לָרָקִיעַ,
and at the Giving of the Torah on Mt. Sinai, G‑d “‘came into His garden’— to His bridal chamber,”2 i.e., He manifested His Presence on this earth again. Thus, it is obvious that the intent of the Midrash is that originally, the Shechinah was manifest on this physical plane. Accordingly,וְעַל יְדֵי מַתַּן תּוֹרָה עַל הַר סִינַי בָּאתִי לְגַנִּי לִגְנוּנִי.
the primary dimension of the withdrawal of the Divine Presence that came about as a result of sin was brought about specifically by the sin of the Tree of Knowledge. For it was as a result of that sin that the Divine Presence withdrew from the earth.וְעִיקַּר הַסִּלּוּק שֶׁנַּעֲשָׂה עַל יְדֵי הַחֵטְא הוּא בְּחֵטְא עֵץ הַדַּעַת דַּוְקָא.
The Midrash, and thus the Rebbe Rayatz in his discourse, mention seven sins. Nevertheless, the Rebbe Rayatz places the sin of the Tree of Knowledge in its own category. To explain: There is a relationship between the seriousness of a sin and its effect.
With regard to the seriousness of the sin,וּכְמוֹ שֶׁבְּעִנְיַן הַחֵטְא,
the primary sin was the sin of the Tree of Knowledge.הֲרֵי עִיקַּר הַחֲטָאִים הָיָה חֵטְא עֵץ הַדַּעַת,
Indeed, the sin of the Tree of Knowledge made all other sins possible.שֶׁהֲרֵי עַל יְדֵי חֵטְא עֵץ הַדַּעַת הָיָה נְתִינַת מָקוֹם לִשְׁאָר הַחֲטָאִים,
It precipitated and brought about the sins of Cain and Enosh as well as later sins.וְחֵטְא עֵץ הַדַּעַת הָיָה סִבָּה וְגוֹרֵם לְהַחֲטָאִים דְּקַיִן וֶאֱנוֹשׁ וְכוּ',
G‑d created man without a tendency to sin. Violating G‑d’s will was totally out of character. After the sin, by contrast, the possibility of sinning existed within a person’s mind and heart and it was necessary to struggle to avoid sinning in the future.3
The same is true with regard to the effect of sin, i.e.,כְּמוֹ כֵן הוּא בִּפְעֻלַּת הַחֵטְא,
the withdrawal of the Shechinah because of the sin:דְּהַסִּלּוּק שֶׁנַּעֲשָׂה עַל יְדֵי הַחֵטְא
the fundamental dimension of the withdrawalof the Shechinah was its withdrawal from this physical world as a result of the sin of the Tree of Knowledge.הִנֵּה עִיקַּר הַסִּלּוּק הוּא מַה שֶׁנִּסְתַּלֵּק עַל יְדֵי חֵטְא עֵץ הַדַּעַת מֵעוֹלָם הַזֶּה הַתַּחְתּוֹן דַּוְקָא,
Just as originally, “The essence of the Shechinah was manifest in the lower realms,” specifically in this physical world,דִּכְשֵׁם שֶׁעִיקַּר שְׁכִינָה בַּתַּחְתּוֹנִים הוּא בָּעוֹלָם הַזֶּה דַּוְקָא,
so too, the fundamental dimension of its withdrawal is its departure from this world.הִנֵּה כְּמוֹ כֵן הוּא בְּהַסִּלּוּק, דְּעִיקַּר הַסִּלּוּק הוּא מַה שֶׁנִּסְתַּלְּקָה מֵהָאָרֶץ דַּוְקָא,
This was brought about by the sin of the Tree of Knowledge.שֶׁזֶּה נַעֲשָׂה עַל יְדֵי חֵטְא עֵץ הַדַּעַת,
It caused the withdrawal of the Shechinah from the earth to heaven.שֶׁעַל יְדֵי זֶה נִסְתַּלְּקָה הַשְּׁכִינָה מֵאֶרֶץ לָרָקִיעַ,
This also explains why (in the maamar) the Rebbe Rayatz does not include the sin of the Tree of Knowledge together with the sins of Cain and Enoshוְזֶהוּ גַּם כֵּן הַטַּעַם שֶׁאֵינוֹ מְצָרֵף (בְּהַמַּאֲמָר) חֵטְא עֵץ הַדַּעַת עִם הַחֲטָאִים דְּקַיִן וֶאֱנוֹשׁ
but lists it separately.וְחוֹשֵׁב זֶה בִּפְנֵי עַצְמוֹ,
The Midrash lists the seven sins that caused the Shechinah to withdraw from the earth and ascend to the higher levels of the heavens in one continuum. In the maamar Basi LeGani, the Rebbe Rayatz places an emphasis on the sin of the Tree of Knowledge, and merely mentions in brief or omits entirely the other sins that caused the further ascent of the Shechinah. The rationale for the distinction is
that the sins of Cain and Enosh, as well as the later sins, caused the Shechinah to ascend merely from one heaven to the next,לְפִי שֶׁבְּהַחֲטָאִים דְּקַיִן וֶאֱנוֹשׁ נִסְתַּלְּקָה הַשְּׁכִינָה מֵרָקִיעַ לָרָקִיעַ,
whereas the sin of the Tree of Knowledge caused its withdrawal from the earth to heaven.מַה שֶּׁאֵין כֵּן בְּחֵטְא עֵץ הַדַּעַת שֶׁנִּסְתַּלְּקָה מֵאֶרֶץ לָרָקִיעַ,
Apart from the fact that the withdrawal from the earthשֶׁלְּבַד זֹאת שֶׁהַסִּלּוּק מֵהָאָרֶץ,
is what primarily affects us,זֶה בְּעִקָּר נוֹגֵעַ לָנוּ,
it is also the fundamental aspect of the withdrawal. For what is of primary importance is that the Shechinah be manifest in this world.הִנֵּה זֶהוּ גַּם עִיקַּר עִנְיַן הַסִּלּוּק.
After mentioning the effect caused by the sin of the Tree of Knowledge and the other sins, the Rebbe Rayatz continues his discourse by quoting the conclusion of the Midrash which highlights the reversal of this process:(וּמַמְשִׁיךְ בַּמַּאֲמָר)
“Afterwards, seven righteous men arose whose Divine service drew the Divine Presence into this world.וְאַחַר כָּךְ עָמְדוּ ז' צַדִּיקִים וְהוֹרִידוּ אֶת הַשְּׁכִינָה לְמַטָּה,
Through the merit of Avraham, the Shechinah was brought down from the seventh heaven to the sixth....”אַבְרָהָם זָכָה וְהוֹרִיד אֶת הַשְּׁכִינָה מֵרָקִיעַ ז׳ לְו׳ כוּ'
(The Rebbe Rayatz abridges his citation of the Midrash and concludes:)(וּמְקַצֵּר בָּזֶה וּמְסַיֵּם)
“...until Moshe, the seventh of these righteous men –עַד כִּי מֹשֶׁה שֶׁהוּא הַשְּׁבִיעִי
here, the Rebbe Rayatz adds a parenthetic statement from another Midrash:4
(“And all those who are seventh are cherished”) –(וְכָל הַשְּׁבִיעִין חֲבִיבִין)
drew the Shechinah into this world below.”הוֹרִידוֹ לְמַטָּה בָּאָרֶץ.
The primary aspect of drawing down the Shechinah was achieved by Moshe,דְּעִיקַּר עִנְיַן הַהַמְשָׁכָה הוּא עַל יְדֵי מֹשֶׁה,
as it was he who drew the Shechinah back into this world.שֶׁהֲרֵי מֹשֶׁה דַּוְקָא הוֹרִידוֹ לְמַטָּה בָּאָרֶץ,
Just as the fundamental element of its withdrawal and ascent upward was the withdrawal from this world caused by the sin of the Tree of Knowledge,דִּכְשֵׁם שֶׁבְּעִנְיַן הַסִּלּוּק מִלְּמַטָּה לְמַעְלָה הֲרֵי הָעִקָּר הוּא בְּחֵטְא עֵץ הַדַּעַת שֶׁנִּסְתַּלֵּק מֵהָאָרֶץ כַּנַּ"ל,
so too, in the reversal that involved drawing down the Shechinah from above,הִנֵּה כְּמוֹ כֵן הוּא בְּעִנְיַן הַהַמְשָׁכָה מִלְמַעְלָה לְמַטָּה,
the fundamental element was drawing it down into this world.עִיקַּר עִנְיַן הַהַמְשָׁכָה הוּא לְמַטָּה בָּאָרֶץ דַּוְקָא,
Apart from the fact that this stage in drawing down the Shechinah is the one that affects us most,דִּלְבַד זֹאת שֶׁהַהַמְשָׁכָה לְמַטָּה בְּעִקָּר נוֹגֵעַ לָנוּ,
it is the most fundamentally important phase in drawing it down.הִנֵּה זֶהוּ גַּם עִיקַּר עִנְיַן הַהַמְשָׁכָה.
Just as in the withdrawal of the Shechinah it was the withdrawal from this earth that was of primary importance, so too, the primary aspect of drawing down the Shechinah is bringing it into this material world.
This was accomplished specifically through Moshe,וְזֶה נַעֲשָׂה עַל יְדֵי מֹשֶׁה דַּוְקָא.
the reason being – as explained in the quote includedin parentheses in the maamar:וְהַטַּעַם לָזֶה מְבָאֵר בְּהַמַּאֲמָר בְּמֻסְגָּר,
“All those who are seventh are cherished.”כִּי כָּל הַשְּׁבִיעִין חֲבִיבִין.

Summary

This section focuses on the term “lower realms” in our Sages’ statement, “The essence of the Shechinah was manifest in the lower realms.” It emphasizes that the intent of this term is this material world. It supports that statement by citing the continuation of the Midrash which states that after the sin of the Tree of Knowledge, the Shechinah withdrew from the lower realms and, at the time of the Giving of the Torah and the construction of the Sanctuary, it returned. From those statements, it is clear that the intent of the term “lower realms” is this material world.
The most significant element of the Shechinah’s withdrawal is its withdrawal from this physical world (and not its subsequent ascent within the hierarchy of the spiritual worlds above) and the most significant element of the process of drawing it back down was drawing it back to this world. The latter was accomplished by Moshe, for Moshe had the distinction of being the seventh in the chain of righteous men whose merits drew the Shechinah downward, as is quoted from the Midrash, and “All those who are seventh are cherished.”