The Alter Rebbe teaches that the vitality and soul of prayer lies in the awakening of the love and awe of God within the heart during prayer; words spoken without this inner movement are compared to a body without a soul, though he also provides comfort for those who struggle to achieve this level.
אַך בִּקְצָרָה בָּאתִי, כְּמַזְכִּיר וּמַחֲזִיר עַל הָרִאשׁוֹנוֹת בִּכְלָל, וּבִפְרָט אֶל הַמִּתְנַדְּבִים בָּעָם, לַעֲמוֹד עַל הָעֲבוֹדָה זוֹ תְּפִלָּה, בְּקוֹל רָם, לְהִתְחַזֵּק מְאֹד בְּכָל עוֹז וְתַעֲצוּמוֹת נֶגֶד כָּל מוֹנֵעַ מִבַּיִת וּמִחוּץ, בְּיָד חֲזָקָה כְּמַשְׁמָעוֹ, שֶׁהוּא ״רְצוֹן יְרֵיאָיו״, אֲשֶׁר לְמַעְלָה מִן הַחָכְמָה וְהַתְּבוּנָה אֲשֶׁר נָתַן ה׳ בָּהֵמָּה לָדַעַת לַעֲשׂוֹת אֶת כָּל אֲשֶׁר צִוָּה ה׳ בְּהַשְׂכֵּל וָדַעַת. רַק רָצוֹן פָּשׁוּט וְ״רוּחַ נְדִיבָה״, בְּכָל אִישׁ אֲשֶׁר יִדְּבֶנּוּ לִבּוֹ לַעֲבוֹד עֲבוֹדָה תַמָּה, לַעֲשׂוֹת נַחַת רוּחַ לְיוֹצְרוֹ. וְעַל זֶה נֶאֱמַר: ״כִּי עַם קְשֵׁה עוֹרֶף הוּא, וְסָלַחְתָּ״. כִּי הַסְּלִיחָה הִיא גַם כֵּן לְמַעְלָה מִן הַחָכְמָה. כִּי ״שָׁאֲלוּ לַחָכְמָה כוּ׳״, וּמשֶׁה רַבֵּינוּ עָלָיו־הַשָּׁלוֹם בִּיקֵּשׁ מִדָּה כְּנֶגֶד מִדָּה, וְדַי לַמֵּבִין.
Briefly, however, I come as one who reminds and repeats erstwhile matters in general, and in particular to those of the people who offer themselves willingly—to stand by the (Divine) service, i.e., prayer, with a loud voice: to strengthen themselves very much with all might and power against any internal or external obstacle, with, literally, a strong hand. This refers to the “will of those who fear Him”—transcending the wisdom and understanding G–d gave into them in order to know to exercise all that G–d commanded with intelligence and knowledge. There should be but a simple will and a spirit of voluntary offering in every one whose heart prompts him to serve “a whole service,” thus to cause gratification to his Maker. Of this it is said: “For it is a stiff-necked people, and You pardon,” for pardon, too, transcends wisdom, as “They asked wisdom….” Thus Moses our Master, peace to him, invoked “measure for measure,” and suffice this for the initiated.