וְשִׁנַּנְתָּ֣ם לְבָנֶ֔יךָ וְדִבַּרְתָּ֖ בָּ֑ם בְּשִׁבְתְּךָ֤ בְּבֵיתֶ֙ךָ֙ וּבְלֶכְתְּךָ֣ בַדֶּ֔רֶךְ וּֽבְשָׁכְבְּךָ֖ וּבְקוּמֶֽךָ׃
и будешь усердно учить их своим детям и говорить о них, когда сидишь в доме твоем, и когда идешь по дороге, и когда ложишься и когда поднимаешься.
Mishnah Berakhot
From what time may one recite the Shema in the evening? From the time that the priests enter [their houses] in order to eat their terumah until the end of the first watch, the words of Rabbi Eliezer. The sages say: until midnight. Rabban Gamaliel says: until dawn. Once it happened that his sons came home [late] from a wedding feast and they said to him: we have not yet recited the [evening] Shema. He said to them: if it is not yet dawn you are still obligated to recite. And not in respect to this alone did they so decide, but wherever the sages say “until midnight,” the mitzvah may be performed until dawn. The burning of the fat and the pieces may be performed till dawn. Similarly, all [the offerings] that are to be eaten within one day may be eaten till dawn. Why then did the sages say “until midnight”? In order to keep a man far from transgression.
Mishnah Shabbat
One may not sit down before a barber near Minhah until he has prayed. One may not enter the baths or a tannery, or [sit down] to eat or [begin] a court case. But if they began, they need not break off. One must break off for the reading of the Shema, but not for prayer.
Mishnah Berakhot
A bridegroom is exempt from reciting the Shema on the first night until the end of the Shabbat, if he has not performed the act. It happened with Rabban Gamaliel who recited the Shema on the first night after he had married. His students said to him: Our master, have you not taught us that a bridegroom is exempt from reciting the Shema. He replied to them: I will not listen to you to remove from myself the Kingship of Heaven even for a moment.