סימן כ סעיף ט
אֵין אוֹמְרִים תְּפִלַּת שְׁמֹנֶה עֶשְׂרֵה בְּקוֹל, אֶלָּא אִם כֵּן יֵשׁ לְכָל הַפָּחוֹת שִׁשָּׁה אֲנָשִׁים, שֶׁהֵם רֹב מִנְיָן שֶׁהִתְפַּלְּלוּ עַתָּה. אֲבָל אִם אֵין שִׁשָּׁה אֲנָשִׁים שֶׁהִתְפַּלְּלוּ עַתָּה, אֵין אוֹמְרִים כָּל הַשְּׁמֹנֶה עֶשְׂרֵה בְּקוֹל, אֶלָּא אֶחָד אוֹמֵר עַד הָאֵל הַקָּדוֹשׁ בְּקוֹל, וְאוֹמְרִים קְדֻשָּׁה וְגוֹמֵר תְּפִלָּתוֹ בְּלַחַשׁ. (ס"ט)
We do not repeat the Shemoneh Esrei aloud, unless there are at least six men who constitute a majority of the minyan, who have finished praying.17“Six men who have finished praying.” The author does not mean that there are only six men assembled. A minyan can never be made up of less than ten men. The author refers to a situation where among the ten assembled there are several who have already prayed. It is still a minyan if there are at least six who are now praying. The others, however, must be present and participate in answering Amein and in saying the Kedusha. But, if there aren't six men who are now praying, we do not repeat the entire Shemoneh Esrei aloud. Instead, one [of those praying] says [from the beginning of Shemoneh Esrei] until Ha'el hakadosh aloud, and everyone says Kedusha, and [the one who said the berachos aloud] completes his Shemoneh Esrei quietly.
תנא דבי אליהו כל השונה הלכות בכל יום מובטח לו שהוא בן העולם הבא שנאמר הליכות עולם לו אל תקרי הליכות אלא הלכות (נדה ע"ג.)