Chapter 76:6-7
The Sabbath and Festival Prayer
6. The abridged form of the Maariv Shemoneh Esrai of Shabbos is recited by
the Chazzan every week of the year, even if Yom Tov (a festival) falls on
Shabbos (1), and even on a Shabbos which falls directly after Yom Tov (2).
However, it is not recited if the first night of Passover falls on Shabbos.
7. This abridged blessing is only recited by the Chazzan in a place where a
Minyan (at least ten adult males) regularly gather for prayer (like a
Synagogue) (3). However, it is not said in places where a Minyan gathers
only on occasion, such as in a wedding hall or a mourner's house (4).
FOOTNOTES:
(1) As we saw in yesterday's footnotes, since, in Talmudic times, the
synagogues were usually situated in the fields outside the city, it would
be dangerous for individuals to be left there alone; consequently, the
Rabbis added this special blessing to the end of the service, in order to
delay the completion of the prayers, thus allowing latecomers to catch up
and then leave the synagogue along with the rest of the congregation. Now,
because the enactment to recite the blessing was due to a concern for
safety, and not due to a specific prayer-related obligation, the Sages did
not require a special mention of Yom Tov in the blessing.
(2) Even though when Shabbos falls directly after Yom Tov, people don't
generally come late to synagogue for Maariv, the abridged version still
must be recited by the Chazzan. This is due to the concept of "Lo Ploog"
(lit: "no differentiation") which basically means that when the Sages made
an enactment, it applies across the board, even in cases where the
reasoning behind the enactment doesn't apply.
(3) This also includes a house where a Minyan regularly gathers for
prayers, as long as they have a Torah Scroll with them (Mishna Berurah 268:24).
(4) These sort of places were never included in the original enactment,
because the reasoning, based on concern for latecomers, doesn't apply
(there is no issue of "Lo Ploog" here, because these places were never part
of the enactment. "Lo Ploog" only applies to situations which are included
in the enactment, and yet, the reasoning doesn't apply to that particular
case). The Magen Avraham writes that those who have the custom to recite
the blessing even in places where there is no regular Minyan, should not be
stopped or rebuked. However, the Pri Megadim disagrees because of the
concern that reciting it in these places might constitute a blessing in vain.