Up to now, the Alter Rebbe has discussed the mitzvah of loving one’s fellow on its own merits. He now proceeds to discuss the value of this mitzvah as the basis for all the commandments, thereby elucidating yet further the importance of “rejoicing with the joy of the soul alone.”

The Talmud relates that it was Hillel the Elder who authored the well-known statement that ahavat Yisrael (the love of one’s fellow Jew) is the basis of the entire Torah. Hillel had been approached by a gentile who declared that he wished to convert to Judaism but only if Hillel would teach him the entire Torah while he stood on one foot. Hillel replied, “What is hateful to you, do not do to your fellow. That is the whole Torah; the rest is but commentary….”

An obvious difficulty presents itself. All mitzvot fall into either of two categories: (a) bein adam lachaveiro—“between man and man” and (b) bein adam laMakom—“between man and G-d.”

It is readily understood how all the mitzvot of the former category may be motivated by one’s love of his fellow. But how can this love motivate one to fulfill any of the mitzvot belonging to the latter category—to observe the Shabbat, for example?

The Alter Rebbe’s answer follows from his previously stated principle that the essence of ahavat Yisrael lies in giving priority to one’s soul rather than to his body. This indeed is the basis of the entire Torah—as the Alter Rebbe continues:

This explains Hillel the Elder’s statement concerning the fulfillment of this mitzvah: “This is the entire Torah; the rest is but commentary.”4

וְזֶהוּ שֶׁאָמַר הִלֵּל הַזָּקֵן עַל קִיּוּם מִצְוָה זוֹ: "זֶהוּ כָּל הַתּוֹרָה כוּלָּהּ, וְאִידָךְ פֵּירוּשָׁא הוּא כוּ'".

For the basis and root purpose of the entire Torah is to elevate and exalt the soul high above the body to [G-d], the source and root of all worlds,

כִּי יְסוֹד וְשׁוֹרֶשׁ כָּל הַתּוֹרָה – הוּא לְהַגְבִּיהַּ וּלְהַעֲלוֹת הַנֶּפֶשׁ עַל הַגּוּף מַעְלָה מַּעְלָה עַד עִיקָּרָא וְשָׁרְשָׁא דְּכָל עָלְמִין

and also to draw down the infinite light of the Ein Sof into the Community of Israel—as will be explained further,5 meaning into the fountainhead of the souls of all Israel, so that “the One [G-d] will reside within [Israel—but only insofar as they are] one,” i.e., united.

וְגַם, לְהַמְשִׁיךְ אוֹר־אֵין־סוֹף בָּרוּךְ־הוּא בִּכְנֶסֶת יִשְׂרָאֵל, כְּמוֹ שֶׁיִּתְבָּאֵר לְקַמָּן, דְּהַיְינוּ, בִּמְקוֹר נִשְׁמוֹת כָּל יִשְׂרָאֵל, לְמֶהֱוֵי אֶחָד בְּאֶחָד דַּוְקָא,

But this indwelling of the light of the Ein Sof in the Community of Israel is impossible if there is disunity between the souls, G-d forbid, for “G-d does not dwell in an imperfect, fragmented place.”6

וְלֹא כְּשֶׁיֵּשׁ פֵּירוּד חַס וְשָׁלוֹם בַּנְּשָׁמוֹת, דְּ"קוּדְשָׁא־בְּרִיךְ־הוּא לָא שַׁרְיָא בַּאֲתַר פְּגִים",

So do we say in our prayers: “Bless us, our Father, all as one with the light of Your Countenance,”7 indicating that “the light of G-d’s Countenance” can be revealed only when we are united “all as one,” as explained elsewhere at length.

וּכְמוֹ שֶׁאוֹמְרִים: "בָּרְכֵנוּ אָבִינוּ כּוּלָּנוּ כְּאֶחָד בְּאוֹר פָּנֶיךָ", וּכְמוֹ שֶׁנִּתְבָּאֵר בְּמָקוֹם אַחֵר בַּאֲרִיכוּת: