1) FROM WHAT TIME MAY WE READ THE SHEMA
QUESTION: Why does Maseches Berachos, the first Masechta of Shas, begin with a discussion of the Mitzvah of Keri'as Shema?
(a) The VILNA GA'ON (Shenos Eliyahu) writes that Shas begins with the Mitzvah of Keri'as Shema because the first Mitzvah that a person is obligated to perform is Keri'as Shema. The Jewish day begins at nightfall, and thus when a young man becomes Bar Mitzvah at age thirteen, the first obligation that he encounters is Keri'as Shema.
(b) The RI'AZ (on the Rif) explains that Shas begins with Keri'as Shema because the Shema is the acceptance of the total dominion of Hash-m and the expression of one's fear of Him. "Reishis Chochmah Yir'as Hash-m" -- "the fear of Hash-m is the beginning of wisdom" (Tehilim 111:10). Therefore, it is appropriate to begin one's quest for Torah wisdom by learning about the Shema, the expression of the fear of Hash-m. "If a person's fear of Hash-m precedes his wisdom, his wisdom will endure" (Avos 3:9).
(c) REBBI TZADOK (Tzidkas ha'Tzadik #3) adds that not only does Keri'as Shema express the acceptance of Hash-m's dominion, but all blessings as well express this concept -- "Blessed are You, Hash-m our G-d, the King of the universe...." While the Shema expresses our acceptance of Hash-m's dominion in a general sense, each blessing expresses it in a specific sense. When we recite a blessing (before or after eating, before performing a Mitzvah, or upon seeing a special sight), we accept Hash-m's dominion over everything in the world. For this reason, the first Maseches in Shas discusses blessings.
Indeed, as Rebbi Tzadok points out, these three themes are all part of one master scheme: every action we do begins with the acceptance of Hash-m's dominion (by reciting a blessing), every day begins with the acceptance of Hash-m's dominion (by reciting the Shema), and one's obligation in the performance of Mitzvos when he becomes Bar Mitzvah begins with the acceptance of Hash-m's dominion (as the Vilna Ga'on writes).
We could add that the Torah itself starts with the acceptance of Hash-m's total authority -- "Bereishis Bara Elokim Es ha'Shamayim v'Es ha'Aretz"; the declaration that Hash-m is the Creator is the expression of His total dominion over the world. This is also implicit in the word "Bereishis," which alludes to the "Reishis Chochmah" of the verse quoted earlier, which, as the verse says, is Yir'as Hash-m.
The year starts with Rosh Hashanah, as the Torah says, "me'Reishis ha'Shanah" -- "from the beginning of the year" (Devarim 11:12). Rosh Hashanah is also a "Reishis." It is the time when we accept upon ourselves the total authority of Hash-m. In addition, through the blowing of the Shofar we express that Hash-m is our King. As with all beginnings, on Rosh Hashanah we start the year by accepting upon ourselves Hash-m's dominion.
2) RECITING THE SHEMA BEFORE NIGHTFALL
OPINIONS: The Mishnah states that the time for Keri'as Shema is after Tzeis ha'Kochavim. RASHI (DH Ad Sof) cites a Yerushalmi that questions the common practice to recite the nighttime Shema and Ma'ariv prayer before Tzeis ha'Kochavim.
(a) RASHI quotes the Yerushalmi that says that we recite the Shema early in order to precede Shemoneh Esreh with words of Torah. We do not fulfill our obligation to recite the Shema at that time, though, and we must recite it again later after Tzeis ha'Kochavim. Rashi says that the recitation of the first paragraph of the Shema before we go to sleep is sufficient to fulfill the obligation.
The ROSH (1:1) adds in the name of Rav Amram Ga'on, the Riva, and the Ritz Ge'as that even though we do not fulfill the obligation of Keri'as Shema when we recite it early, we may still recite the blessings before and after the Shema.
(b) RABEINU TAM (cited by Tosfos DH me'Eimasai) explains that we do fulfill the obligation of Keri'as Shema when we recite it before Tzeis ha'Kochavim. There is an argument between Rebbi Yehudah and the Rabanan (26a) regarding the time for reciting Minchah and Ma'ariv. Rebbi Yehudah maintains that one may recite Minchah until "Plag ha'Minchah," or 10 3/4 hours into the day (1 1/4 hours before nightfall) and recite Ma'ariv after that point. If the time for Ma'ariv begins 1 1/4 hours before nightfall, the time for Keri'as Shema also begins then. Rabeinu Tam says that we rule that one is permitted to follow the opinion of Rebbi Yehudah, and therefore we may recite the Shema before Tzeis ha'Kochavim.
(c) The RI (cited by Tosfos) and the ROSH disagree with Rabeinu Tam. They explain the reason we recite the Shema before Tzeis ha'Kochavim as follows. There are several different opinions cited in the Gemara regarding the earliest time one may recite the Shema. We rule in accordance with the opinion that says that the earliest time to recite the Shema is when the day becomes sanctified on the eve of Shabbos (or when people eat on Erev Shabbos), which is before Tzeis ha'Kochavim (see Chart #1, Berachos 2b). It follows that Ma'ariv may also be recited at that time.
HALACHAH: The Rosh writes that one should not rely on the Ri except in extenuating circumstances, because the proper time for Keri'as Shema is not until after Tzeis ha'Kochavim.
What does one do when he finds himself in a place where the Minyan for Ma'ariv is early? The Mishnah Berurah suggests three possibilities:
1. According to some authorities, he may recite Ma'ariv with them and then say the Shema again later, after Tzeis ha'Kochavim.
2. Other authorities maintain that one should not recite the blessings of the Shema without fulfilling the obligation of Keri'as Shema. Rather, he should recite Shemoneh Esreh with the Minyan and, later, after nightfall, he should recite the Shema with its blessings.
3. The VILNA GA'ON (cited by the Bi'ur Halachah 235:1, DH v'Im ha'Tzibur) rules that it is better to pray alone after Tzeis ha'Kochavim than to pray before Tzeis ha'Kochavim with a Minyan.