אֲמַר לֵיהּ רַבִּי יִצְחָק לְרַב נַחְמָן: מַאי טַעְמָא לָא אָתֵי מָר לְבֵי כְּנִישְׁתָּא לְצַלּוֹיֵי? אֲמַר לֵיהּ: לָא יָכֵילְנָא. אֲמַר לֵיהּ: לִכַּנְפִי לְמָר עַשְׂרָה וְלִיצַלֵּי. אֲמַר לֵיהּ: טְרִיחָא לִי מִלְּתָא. וְלֵימָא לֵיהּ מָר לִשְׁלוּחָא דְצִבּוּרָא, בְּעִידָּנָא דִּמְצַלֵּי צִבּוּרָא לֵיתֵי וְלוֹדְעֵיהּ לְמָר.
As a prelude to another of the statements by Rabbi Yoḥanan in the name of Rabbi Shimon ben Yoḥai, the Gemara relates the following incident. Rabbi Yitzḥak said to Rav Naḥman: Why did the Master not come to the synagogue to pray? Rav Naḥman said to him: I was weak and unable to come. Rabbi Yitzḥak said to him: Let the Master gather ten individuals, a prayer quorum, at your home and pray. Rav Naḥman said to him: It is difficult for me to impose upon the members of the community to come to my home to pray with me (Sefer Mitzvot Gadol). Rabbi Yitzḥak suggested another option: The Master should tell the congregation to send a messenger when the congregation is praying to come and inform the Master so you may pray at the same time.
אֲמַר לֵיהּ מַאי כּוּלֵּי הַאי? אֲמַר לֵיהּ דְּאָמַר רַבִּי יוֹחָנָן מִשּׁוּם רַבִּי שִׁמְעוֹן בֶּן יוֹחַי:
Rav Naḥman saw that Rabbi Yitzḥak was struggling to find a way for him to engage in communal prayer. He asked: What is the reason for all this fuss? Rabbi Yitzḥak said to him: As Rabbi Yoḥanan said in the name of Rabbi Shimon ben Yoḥai:
מַאי דִּכְתִיב ״וַאֲנִי תְפִלָּתִי לְךָ ה׳ עֵת רָצוֹן״. אֵימָתַי עֵת רָצוֹן — בְּשָׁעָה שֶׁהַצִּבּוּר מִתְפַּלְּלִין.
What is the meaning of that which is written: “But as for me, let my prayer be unto You, Lord, in a time of favor; O God, in the abundance of Your mercy, answer me with the truth of Your salvation” (Psalms 69:14)? It appears that the individual is praying that his prayers will coincide with a special time of Divine favor. When is a time of favor? It is at the time when the congregation is praying. It is beneficial to pray together with the congregation, for God does not fail to respond to the entreaties of the congregation.
מַתְנִי׳ לֹא יֵשֵׁב אָדָם לִפְנֵי הַסַּפָּר סָמוּךְ לַמִּנְחָה עַד שֶׁיִּתְפַּלֵּל. לֹא יִכָּנֵס אָדָם לַמֶּרְחָץ, וְלֹא לַבּוּרְסְקִי, וְלֹא לֶאֱכוֹל, וְלֹא לָדִין, וְאִם הִתְחִילוּ — אֵין מַפְסִיקִין. מַפְסִיקִין לִקְרוֹת קְרִיאַת שְׁמַע וְאֵין מַפְסִיקִין לִתְפִלָּה.
MISHNA: After having dealt with the limited and defined topic of the halakhot of carrying out on Shabbat, the mishna begins to deal with the halakhot of Shabbat chronologically, beginning with activities that one may not perform prior to the onset of Shabbat. With regard to one’s daily conduct, the mishna says: A person may not sit before the barber adjacent to the time of minḥa until he recites the afternoon prayer. And a person may not enter the bathhouse and may not enter to work in a tannery [burseki]. And he may neither begin to eat a meal nor to sit in judgment until he prays. And however, if they already began engaging in those activities, they need not stop and recite the Amida prayer. The tanna articulated a principle: One stops engaging in all of these activities to recite Shema and one does not stop to recite the Amida prayer.
Rav Soloveitchik: On Repentance - the Erev Shabbat Jew
"Even in those neighborhoods made up predominantly of religious Jews, one can no longer talk of the 'sanctity of Shabbat.' True, there are Jews in America who observe Shabbat...But it is not for Shabbat that my heart aches; it is for the forgotten 'erev Shabbat' (eve of the Sabbath).There are Shabbat-observing Jews in America, but there are no 'erev Shabbat' Jews who go out to greet Shabbat with beating hearts and pulsating souls. There are many who observe the precepts with their hands, with their feet, and/or with their mouths - but there are few indeed who truly know the meaning of the service of the heart!"