"And you shall make boards"
Rabbi Shimon here says that the boards in "And you shall make boards for the Tabernacle of acacia wood standing up" are like the Seraphim standing each with their six wings. All the hosts of heaven stand, and the supernal angels are sometimes referred to as 'Seraphim'.
The tabernacle was the Vessel necessary for the Light to express itself on this planet. Here Rabbi Shimon reveals supernal secrets behind the construction of the tabernacle. His purpose in doing so is to construct a personal tabernacle, an internal vessel, for the reader through his holy words so that God's Light can rest upon us. Moreover, this action connects our planet to the original Tabernacle, allowing God's Light to inhabit the entire world, causing the demise of death, suffering, pain, and torment. Expect nothing less when such a magnificent instrument is wielded in the hands of so noble a sage.
806. This was the commandment of the Holy One, blessed be He, to Moses, "And you shall make boards for the Tabernacle of acacia wood standing up" (Shemot 26:15). It is written, "Seraphim stood above Him, each one had six wings... " (Yeshayah 6:2). For the construction of the Tabernacle with these boards resembled these Seraphim. The ones were standing and the others were standing.
806. דָּא פִּקּוּדָא דְּקוּדְשָׁא בְּרִיךְ הוּא לְמֹשֶׁה: וְעָשִׂיתָ אֶת הַקְּרָשִׁים לַמִּשְׁכָּן עֲצֵי שִׁטִּים עוֹמְדִים. וּכְתִיב שְׂרָפִים עוֹמְדִים מִמַּעַל לוֹ שֵׁשׁ כְּנָפַיִם וְגוֹ,' עוֹבָדָא דְּמַשְׁכְּנָא בְּאִינּוּן קְרָשִׁים, כְּגַוְונָא דְּאִינּוּן שְׂרָפִים, אִלֵּין עוֹמְדִים, וְאִלֵּין עוֹמְדִים.
807. If you say that all the hosts of heaven stand, as it is written, "Then I will give you access among these who stand by" (Zecharyah 3:7) and "all the host of heaven standing by Him... " (I Melachim 22:19). Do all the supernal camps have no joints, NAMELY KNEES TO KNEEL AND SIT, so they all stand? HE ANSWERS, Surely they all stand. They are sometimes called 'Seraphim' and sometimes with a different name, but these IN THE VERSE "SERAPHIM STOOD ABOVE HIM" always bear the same name, SERAPHIM. AND THE COMPARISON OF THE BOARDS OF THE TABERNACLE TO SERAPHIM IS TRUE WITH ALL THE SUPERNAL ANGELS, BECAUSE THEY ARE ALL REFERRED TO AS SERAPHIM OCCASIONALLY BUT THEY ARE NOT EXACTLY LIKE THE SERAPHIM IN THE VERSE, "SERAPHIM STOOD ABOVE HIM... "
807. וְאִי תֵּימָא, וְהָא כָּל חַיָּילֵי שְׁמַיָא אִינּוּן עוֹמְדִים כֻּלְּהוּ, כד"א וְנָתַתִּי לְךָ מַהְלְכִים בֵּין הָעוֹמְדִים הָאֵלֶּה, וּכְתִיב וְכָל צְבָא הַשָּׁמַיִם עוֹמְדִים עָלָיו וְגוֹ,' דְּהָא כֻּלְּהוּ מַשִּׁרְיָין עִלָּאִין לֵית לְהוּ קְפִיצִין, וְכֻלְּהוּ קַיְימֵי בְּקִימָה. אֶלָּא וַדַּאי כֻּלְּהוּ קַיְימִין, וּלְזִמְנִין אִלֵּין אִקְרוּן שְׂרָפִים, וּלְזִמְנִין סַלְּקִין בִּשְׁמָא אַחֲרָא, אֲבָל אִלֵּין כֻּלְּהוּ בְּחַד שְׁמָא קַיְימֵי.