ברכות ה׳Berakhot 5

Mishnah 1א׳

אֵין עוֹמְדִין לְהִתְפַּלֵּל אֶלָּא מִתּוֹךְ כֹּבֶד רֹאשׁ. חֲסִידִים הָרִאשׁוֹנִים הָיוּ שׁוֹהִים שָׁעָה אַחַת וּמִתְפַּלְּלִים, כְּדֵי שֶׁיְּכַוְּנוּ אֶת לִבָּם לַמָּקוֹם. אֲפִלּוּ הַמֶּלֶךְ שׁוֹאֵל בִּשְׁלוֹמוֹ, לֹא יְשִׁיבֶנּוּ. וַאֲפִלּוּ נָחָשׁ כָּרוּךְ עַל עֲקֵבוֹ, לֹא יַפְסִיק:

[One] should not stand up to pray unless he is in a serious frame of mind. The original pious ones used to wait one hour and then pray, in order to direct their hearts towards the Omnipresent. [While one is reciting Shemoneh Esrei,] even if the king greets him, he should not respond to him, and even if a snake wraps around his heel, he should not interrupt.

Mishnah 2ב׳

מַזְכִּירִין גְּבוּרוֹת גְּשָׁמִים בִּתְחִיַּת הַמֵּתִים, וְשׁוֹאֲלִין הַגְּשָׁמִים בְּבִרְכַּת הַשָּׁנִים, וְהַבְדָּלָה בְּחוֹנֵן הַדָּעַת. רַבִּי עֲקִיבָא אוֹמֵר, אוֹמְרָהּ בְּרָכָה רְבִיעִית בִּפְנֵי עַצְמָהּ. רַבִּי אֱלִיעֶזֶר אוֹמֵר, בְּהוֹדָאָה:

[We] mention the request for rain in [the blessing of] Techiyat HaMeitim [Resurrection of the Dead]; and [we] ask for rain [by adding the phrase Vetein Tal Umatar Livrakhah] in Birkat HaShanim [Blessing of the Year's crops]; and [we recite] Havdalah [blessing for the transition from Sabbath to weekday] in [the blessing of] Chonein Hada'at [Endower of Knowledge]. Rabbi Akiva says: One recites it [Havdalah] as a fourth blessing by itself. Rabbi Eliezer says: [One recites Havdalah] in the blessing of Modim [Thanksgiving].