The Sabbath and Festival Prayer
1. It is customary to recite the Maariv (evening service) of Shabbos
earlier than one usually recites Maariv during the week. It is proper to do
so, in order to begin Shabbos (1) as early as possible (2), as long as its
after "Plag HaMincha" (3). Even those who generally recite Maariv at its
proper time, that is, after the appearance of three stars (4), may recite
it earlier on Shabbos.
Although during the week people occasionally recite Mincha (afternoon
service) at the same time that they are now reciting the Maariv of Shabbos,
there is no reason to be concerned in this case (5), because [by reciting
the Maariv of Shabbos early], one fulfills the Mitzvah of adding time from
the "Non-Holy" to the "Holy.(6)"
(1) In Talmudic times, it was customary to begin Shabbos with the recital
of "Barchu" at the beginning of Maariv. According to the Mishna Berura
(261:30), nowadays, when the congregation in
Synagogue sing the words "Boie Challah" ("Welcome Bride") in the song
"Lecha Dodi," (recited just before Maariv) they are accepting Shabbos upon
(2) There are two reasons for beginning Shabbos early. Firstly, most
authorities rule that it is a Mitzvah to begin Shabbos while it is still
considered to be "daytime" on Friday, i.e., before sunset. This concept is
called "Mosif Mechol Al HaKodesh" (lit: "adding part of the non-holy to the
holy"). Secondly, even those authorities who rule that it is not an actual
Mitzvah to begin Shabbos early, still rule that everyone should refrain
from performing prohibited acts a short time before sunset, because if one
got into the habit of waiting until a moment before sunset to begin
Shabbos, one could easily end up performing a prohibited act after sunset
(See Shulchan Aruch 261 and commentaries). In many communities, the women
would wait to light candles until they saw that the evening prayers were
beginning in the synagogue; consequently, if Maariv wasn't recited early
(before sunset), many would end up lighting candles after sunset, thereby
desecrating the Shabbos (Aruch HaShulchan 267:4).
(3) It is permissible to begin Shabbos anytime after "Plag HaMincha" on
Friday afternoon, which is always one and a quarter seasonal hours ("Shaos
Zemanios") before sunset (a "seasonal hour" is equal to one twelfth of the
total time from sunrise to sunset (some say from dawn to dark) ) (See Rema
(4) Three small stars which are relatively close to each other.
(5) There is a dispute in the Talmud as to what is the correct time frame
within which to recite Mincha and Maariv. Rabbi Yehuda rules that one can
only recite Mincha up to "Plag HaMincha" (see note 3), and from then
onwards, one can recite Maariv. The Rabbis, however, rule that the time for
Mincha extends until nightfall (in practical terms, this means sunset,
because after that point we are not sure when nighttime actually begins),
and one can only recite Maariv after nightfall (that is, from the time we
are certain that nighttime has begun, which is when 3 stars appear).
Now, it is generally forbidden for those who customarily follow the Rabbis,
by waiting until after nightfall to recite Maariv, to randomly decide to
pray Maariv before nightfall, like the ruling of Rabbi Yehuda. However,
since by praying Maariv of Shabbos before sunset, one is fulfilling the
Mitzvah of adding from the non-holy to the holy (see note 2) by accepting
Shabbos early, the authorities permitted changing one's custom in this
case. However, when following Rabbi Yehuda by praying Maariv before sunset,
one must be careful to be consistent and follow his ruling regarding Mincha
as well, that is, by praying Mincha before "Plag HaMincha." There is an
opinion which states that if one is praying with the congregation, one may
pray Maariv before sunset, even if one prayed Mincha after "Plag HaMincha."
However, the Mishna Berura (267:3) rules that one can only rely on that
leniency in pressing circumstances, and only if one waits until after
sunset to pray Maariv (that is, during "Bein HaShemashos", the time period
in which we are uncertain whether it is "day" or "night").
(6) See note (2).