Berakhot 2:16

['The first question discussed in the mishna is the question of intent. One who was reading the sections of the Torah which comprise Shema, and the time for the recitation of the morning or evening Shema arrived, if he focused his heart, he fulfilled his obligation and need not repeat Shema in order to fulfill his obligation. This is true even if he failed to recite the requisite blessings (Rabbeinu Ḥananel). Ab initio, one may not interrupt the recitation of Shema. The tanna’im, however, disagree over how strict one must be in this regard. They distinguish between interruptions between paragraphs and interruptions within each paragraph. At the breaks between paragraphs, one may greet an individual due to the respect that he is obligated to show him, and one may respond to another’s greeting due to respect. And in the middle of each paragraph one may greet an individual due to the fear that the individual may harm him if he fails do so (Me’iri) and one may respond to another’s greeting due to fear. This is the statement of Rabbi Meir. Rabbi Yehuda says: There is a distinction between greeting someone and responding to his greeting. In the middle of each paragraph, one may greet another due to fear and respond due to respect. In the breaks between paragraphs, one may greet another due to respect and respond with a greeting to any person who greets him, whether or not he is obligated to show him respect.', 'As for what constitutes a paragraph, these are the breaks between the paragraphs: Between the first blessing and the second, between the second and Shema, between Shema and the second paragraph: If you indeed heed My commandments [VeHaya im Shamoa], between VeHaya im Shamoa and the third paragraph: And the Lord spoke [VaYomer] and between VaYomer and True and Firm [emet veyatziv], the blessing that follows Shema. The Rabbis held that each blessing and each paragraph of Shema constitutes its own entity, and treat interruptions between them as between the paragraphs. Rabbi Yehuda, however, says: Between VaYomer and emet veyatziv, which begins the blessing that follows Shema, one may not interrupt at all. According to Rabbi Yehuda, these must be recited consecutively. Since the paragraphs of Shema are not adjacent to one another in the Torah, and they are not recited in the order in which they appear, the mishna explains their placement. Rabbi Yehoshua ben Korḥa said: Why, in the mitzva of the recitation of Shema, did the portion of Shema precede that of VeHaya im Shamoa? This is so that one will first accept upon himself the yoke of the kingdom of Heaven, the awareness of God and God’s unity, and only then accept upon himself the yoke of the mitzvot, which appears in the paragraph of VeHaya im Shamoa. Why did VeHaya im Shamoa precede VaYomer? Because the paragraph of VeHaya im Shamoa is practiced both by day and by night, while VaYomer, which discusses the mitzva of ritual fringes, is only practiced during the day.', 'One who recites Shema and did not recite in a manner audible to his own ear, either because he read inaudibly or because he is deaf, fulfilled his obligation. Rabbi Yosei says: He did not fulfill his obligation. One who recited Shema and was not sufficiently precise in his enunciation of its letters, Rabbi Yosei says: He fulfilled his obligation. Rabbi Yehuda says: He did not fulfill his obligation. One who recited Shema out of order, meaning he did not read the verses sequentially, he did not fulfill his obligation. One who recited and erred, should return to the place in Shema that he erred.', 'The primary issue in this mishna is the requisite degree of concentration when reciting Shema. Laborers engaged in their work may recite Shema while standing atop the tree or atop the course of stones in a wall under construction, which they are not permitted to do for the Amida prayer, which requires intent of the heart.', 'The mishna continues: A groom is exempt from the recitation of Shema on the first night of his marriage, which was generally Wednesday night, until Saturday night, if he has not taken action and consummated the marriage, as he is preoccupied by concerns related to consummation of the marriage. The mishna relates that there was an incident where Rabban Gamliel married a woman and recited Shema even the first night. His students said to him: Didn’t our teacher teach us that a groom is exempt from the recitation of Shema? He answered them: Nevertheless, I am not listening to you to refrain from reciting Shema, and in so doing preclude myself from the acceptance of the yoke of the Kingdom of Heaven, for even one moment.', 'The mishna relates another episode portraying unusual conduct by Rabban Gamliel. He bathed on the first night after his wife died. His students said to him: Have you not taught us, our teacher, that a mourner is prohibited to bathe? He answered them: I am not like other people, I am delicate [istenis]. For me, not bathing causes actual physical distress, and even a mourner need not suffer physical distress as part of his mourning.', 'Another exceptional incident is related: And when his slave, Tavi, died, Rabban Gamliel accepted condolences for his death as one would for a close family member. His students said to him: Have you not taught us, our teacher, that one does not accept condolences for the death of slaves? Rabban Gamliel said to his students: My slave, Tavi, is not like all the rest of the slaves, he was virtuous and it is appropriate to accord him the same respect accorded to a family member.', 'With regard to the recitation of Shema on one’s wedding night, the Sages said that if, despite his exemption, a groom wishes to recite Shema on the first night, he may do so. Rabban Shimon ben Gamliel says: Not everyone who wishes to assume the reputation of a God-fearing person may assume it, and consequently, not everyone who wishes to recite Shema on his wedding night may do so.']