רַבֵּנוּ הַזָּקֵן כּוֹתֵב בְּסִדּוּרוֹ: נָכוֹן לוֹמַר קוֹדֶם הַתְּפִלָּה הֲרֵינִי מְקַבֵּל עָלַי מִצְוַת עֲשֵׂה שֶׁל וְאָהַבְתָּ לְרֵעֲךָ כָּמוֹךָ. זֹאת אוֹמֶרֶת, אֲשֶׁר מִצְוַת אַהֲבַת יִשְׂרָאֵל הִיא שַׁעַר הַכְּנִיסָה, אֲשֶׁר דֶּרֶךְ בּוֹ יָכוֹל הָאָדָם לָבוֹא לַעֲמוֹד לִפְנֵי ה' אֱלֹקֵנוּ לְהִתְפַּלֵּל, בִּזְכוּתָהּ תְּקוּבָּל תְּפִלַּת הַמִּתְפַּלֵּל.

The Alter Rebbe writes in his Siddur1 that it is appropriate to say before [the morning] prayers: “I hereby undertake to fulfill the commandment, ‘Love your fellowman as yourself.’ “

This implies that fulfilling the mitzvah of ahavas Yisrael is the gateway through which a person is enabled to enter and stand before G‑d in prayer, and in the merit of [this mitzvah] one’s prayers are accepted.2

Probing Beneath the Surface

In Derech Mitzvosecha,3 the Tzemach Tzedek explains this statement on a mystical level. When we pray, we offer ourselves as a sacrifice to G‑d, as it were,4 and a sacrifice that is to be offered on the altar must be without blemish.5 Now, every Jew is intrinsically connected with every other member of the House of Israel. In the words of the AriZal, the souls of all Jews together comprise “the mystical principle of one body.”6 Hence, if any individual is to be a perfect sacrifice he must perceive himself as being united with all his fellows, with all the other limbs of the same body. If in his heart he cuts himself off from even one solitary Jew, both he and his offering are blemished and hence unacceptable.7