The beginning of tractate Berakhot, the first tractate in the first of the six orders of Mishna, opens with a discussion of the recitation of Shema, as the recitation of Shema encompasses an acceptance of the yoke of Heaven and of the mitzvot, and as such, forms the basis for all subsequent teachings. The Mishna opens with the laws regarding the appropriate time to recite Shema:
From when, that is, from what time, does one recite Shema in the evening? From the time when the priests enter to partake of their teruma. Until when does the time for the recitation of the evening Shema extend? Until the end of the first watch. The term used in the Torah (Deuteronomy 6:7) to indicate the time for the recitation of the evening Shema is beshokhbekha, when you lie down, which refers to the time in which individuals go to sleep. Therefore, the time for the recitation of Shema is the first portion of the night, when individuals typically prepare for sleep. That is the statement of Rabbi Eliezer. The Rabbis say: The time for the recitation of the evening Shema is until midnight. Rabban Gamliel says: One may recite Shema until dawn, indicating that beshokhbekha is to be understood as a reference to the entire time people sleep in their beds, the whole night. The mishna relates that Rabban Gamliel practiced in accordance with his ruling. There was an incident where Rabban Gamliel’s sons returned very late from a wedding hall. They said to him, as they had been preoccupied with celebrating with the groom and bride: We did not recite Shema. He said to them: If the dawn has not yet arrived, you are obligated to recite Shema. Since Rabban Gamliel’s opinion disagreed with that of the Rabbis, he explained to his sons that the Rabbis actually agree with him, and that it is not only with regard to the halakha of the recitation of Shema, but rather, wherever the Sages say until midnight, the mitzva may be performed until dawn. Rabban Gamliel cites several cases in support of his claim, such as the burning of fats and limbs on the altar. Due to the quantity of offerings each day, the priests were often unable to complete the burning of all of the fats and limbs, so they continued to be burned into the night, as it is written: “This is the law of the burnt offering: The burnt offering shall remain upon the pyre on the altar all night until morning, while the fire on the altar burns it” (Leviticus 6:2). And, with regard to all sacrifices, such as the sin-offerings and the guilt-offerings that are eaten for one day and night; although the Sages state that they may be eaten only until midnight, by Torah law they may be eaten until dawn. This is in accordance with the verse: “On the day on which it is offered must you eat. Do not leave it until the morning” (Leviticus 7:15). If so, why did the Sages say that they may be eaten only until midnight? This is in order to distance a person from transgression, as if one believes that he has until dawn to perform the mitzva, he might be negligent and postpone it until the opportunity to perform the mitzva has passed.
From when does one recite Shema in the morning? From when a person can distinguish between sky-blue [tekhelet] and white.
Rabbi Eliezer says: From when one can distinguish between sky-blue and leek-green.
And one must finish reciting Shema until the end of the period when you rise, i.e., sunrise, when the sun begins to shine.
Rabbi Yehoshua says: One may recite the morning Shema until three hours of the day, which this is still considered when you rise, as that is the habit of kings to rise from their sleep at three hours of the day. While there is a set time frame for the recitation of Shema, one who recites Shema from that time onward loses nothing. Although he does not fulfill the mitzva of reciting of Shema at its appointed time, he is nevertheless considered like one who reads the Torah, and is rewarded accordingly.
Beit Shammai and Beit Hillel disputed the proper way to recite Shema. Beit Shammai say: One should recite Shema in the manner indicated in the text of Shema itself. Therefore, in the evening every person must recline on his side and recite Shema, in fulfillment of the verse: “When you lie down,” and in the morning he must stand and recite Shema, in fulfillment of the verse: When you rise, as it is stated: “When you lie down, and when you rise.” And Beit Hillel say: Every person recites Shema as he is, and he may do so in whatever position is most comfortable for him, both day and night, as it is stated: “And when you walk along the way,” when one is neither standing nor reclining (Me’iri). If so, according to Beit Hillel, why was it stated: “When you lie down, and when you rise”? This is merely to denote time; at the time when people lie down and the time when people rise. With regard to this halakha, Rabbi Tarfon said: Once, I was coming on the road when I stopped and reclined to recite Shema in accordance with the statement of Beit Shammai. Although Rabbi Tarfon was a disciple of Beit Hillel, he thought that fulfilling the mitzva in accordance with the opinion of Beit Shammai would be a more meticulous fulfillment of the mitzva, acceptable to all opinions. Yet in so doing, I endangered myself due to the highwaymen [listim] who accost travelers. The Sages said to him: You deserved to be in a position where you were liable to pay with your life, as you transgressed the statement of Beit Hillel. This statement will be explained in the Gemara.
From the laws of the recitation of Shema itself, the mishna proceeds to discuss the blessings recited in conjunction with Shema. Here, the order is established: In the morning when reciting Shema, one recites two blessings beforehand, the first on the radiant lights and the second the blessing on the love of Torah, and one thereafter, which begins with: True and Firm [emet veyatziv]. And in the evening one recites two blessings beforehand, on the radiant lights and on the love of God, and two thereafter, the blessing of redemption: True and Faithful [emet ve’emuna], and the blessing: Help us lie down. With regard to the blessing: True and Faithful, whether one recites it in its long formula and whether one recites it in its short formula, he fulfills his obligation (Tosafot). However, the general principle is: Where the Sages said to recite a long blessing, one may not shorten it, and so too, wherever they said to recite a short blessing, one may not lengthen it. Where the Sages said that a blessing must conclude with a second blessing at the end, he may not fail to conclude with that blessing. Similarly, if the Sages said that a blessing must not conclude with a second blessing, one may not conclude with a blessing.
It is a mitzva by Torah law to mention the exodus from Egypt at night, but some held that this mitzva was, like phylacteries or ritual fringes, fulfilled only during the day and not at night. For this reason it was decided: The exodus from Egypt is mentioned at night, adjacent to the recitation of Shema. Rabbi Elazar ben Azarya said: I am approximately seventy years old, and although I have long held this opinion, I was never privileged to prevail (Me’iri) and prove that there is a biblical obligation to fulfill the accepted custom (Ra’avad) and have the exodus from Egypt mentioned at night, until Ben Zoma interpreted it homiletically and proved it obligatory. Ben Zoma derived it as it is stated: “That you may remember the day you went out of the land of Egypt all the days of your life” (Deuteronomy 16:3). The days of your life, refers to daytime alone; however, the addition of the word all, as it is stated: All the days of your life, comes to add nights as well. And the Rabbis, who posit that there is no biblical obligation to mention the exodus from Egypt at night, explain the word, all, differently and say: The days of your life, refers to the days in this world, all is added to include the days of the Messiah.