Having stated that love and fear of G-d elevate one’s Torah and mitzvot on high, the Alter Rebbe continues:

This explains clearly why fear and love are figuratively called “wings,” as it is written: “And with two wings he flies,”11 alluding to the two middot of love and fear

וּבָזֶה יוּבַן הֵיטֵב, הָא דִּדְחִילוּ וּרְחִימוּ נִקְרָאִין "גַּדְפִין" דֶּרֶךְ מָשָׁל, כְּדִכְתִיב: "וּבִשְׁתַּיִם יְעוֹפֵף"

(12as Rabbi Chaim Vital, of blessed memory, stated in Shaar Hayichudim,13 ch. 11), that wings are for a bird what arms are for a man; just as it is written, “chesed (corresponding to love) is the right arm and gevurah (fear) the left arm,” similarly, the “wings” represent these two middot.

[וּכְמוֹ שֶׁכָּתַב הָרַב חַיִּים וִיטַאל זִכְרוֹנוֹ לִבְרָכָה בְּשַׁעַר הַיִּחוּדִים פֶּרֶק י"א], שֶׁהַכְּנָפַיִם בָּעוֹף הֵן זְרוֹעוֹת הָאָדָם כוּ';

It is also explained in Tikkunei Zohar, that those who engage in Torah and mitzvot out of fear and love are called “children”;

וּבַתִּיקּוּנִים פֵּירְשׁוּ, שֶׁהָעוֹסְקִים בְּתוֹרָה וּמִצְוֹת בִּדְחִילוּ וּרְחִימוּ – נִקְרָאִים "בָּנִים",

otherwise (i.e., if their Torah and mitzvot lack the fear and love of G-d), they are called “fledglings” who cannot fly.

וְאִם לָאו – נִקְרָאִים "אֶפְרוֹחִים", דְּלָא יָכְלִין לְפָרְחָא.

In this note, the Alter Rebbe elaborates on the correspondence of “wings” to fear and love. He quotes Tikkunei Zohar, where the subject is treated extensively.

In Tikkun 45, it is written that [the figure of] a bird represents the archangel Metatron.

וּבְתִיקּוּן מ"ה, דְּעוֹפָא הוּא מט"ט,

His head is the letter yud of the Divine Name (yud-hey-vav-hey), the yud representing chochmah; his body is the vav, the six middot; and his two wings are the two letters hey and hey, representing binah and malchut, respectively.

רֵישָׁא דִילֵיהּ – י', וְגוּפָא – וָא"ו, וּתְרֵין גַּדְפִין – ה' ה' כוּ',

This corresponds to the World of Yetzirah, which is called Metatron.

וְהַיְינוּ עוֹלַם הַיְצִירָה שֶׁנִּקְרָא מט"ט,

Thus, applying the various elements of the figure to their corresponding aspects in Yetzirah, we obtain:

14Vav, the “body” of Metatron, represents the “body” of the laws in the Mishnah (since Mishnah is at the level of Yetzirah, as will soon be explained), for the “body” of the laws, i.e., the actual rulings determining what is permitted or forbidden, who is guilty or innocent, and the like, are related to the middot, which are represented by the letter vav.

וּבוֹ הֵן גּוּפֵי הֲלָכוֹת שֶׁבַּמִּשְׁנָה,

His head represents intelligence—the level of ChaBaD, which are, in terms of the Mishnah, the inner depth of the laws, their esoteric meaning, and their reasons.

וְרֵישָׁא דִילֵיהּ הֵן הַמּוֹחִין וּבְחִינוֹת חָכְמָה בִּינָה דַּﬠַת, שֶׁהֵן פְּנִימִיּוּת הַהֲלָכוֹת וְסוֹדָן וְטַﬠֲמֵיהֶן,

The two “wings” denoting flight, namely fear and love, represent [respectively]: the higher hey, which is an allusion prevalent in the literature of the Kabbalah to love,

וּתְרֵין גַּדְפִין דְּחִילוּ וּרְחִימוּ הֵן ה' ﬠִילָּאָה, שֶׁהִיא רְחִימוּ,

and the lower hey, alluding to “lower-level fear,” namely, “the yoke of the Heavenly Kingdom” and the dread of G-d similar to the dread of a king.

וְה' תַּתָּאָה הִיא יִרְאָה תַּתָּאָה, עוֹל מַלְכוּת שָׁמַיִם וּפַחַד ה', כְּפַחַד הַמֶּלֶךְ דֶּרֶךְ מָשָׁל,

Such fear is external and revealed and is therefore alluded to by the lowest level (i.e., letter) of the Divine Name.

שֶׁהִיא יִרְאָה חִיצוֹנִית וְנִגְלֵית;

“Higher-level fear,” however, meaning “awe consisting of shame before G-d’s greatness,” is of those “hidden matters belonging to G-d, our L-rd.”

מַה שֶּׁאֵין כֵּן יִרְאָה ﬠִילָּאָה, יְרֵא בּוֹשֶׁת, הִיא מֵ"הַנִּסְתָּרוֹת לַה' אֱלֹהֵינוּ",

It is on the level of supernal wisdom, alluded to by the yud of the Four-letter Divine Name, blessed be He, as is written in Raaya Mehemna.

וְהִיא בְּחָכְמָה ﬠִילָּאָה יוּ"ד שֶׁל שֵׁם הֲוָיָ"ה בָּרוּךְ־הוּא, כְּמוֹ שֶׁכָּתוּב בְּרַﬠְיָא מְהֵימְנָא: