ברכות א׳Berakhot 1

Mishnah 1א׳

מֵאֵימָתַי קוֹרִין אֶת שְׁמַע בְּעַרְבִית. מִשָּׁעָה שֶׁהַכֹּהֲנִים נִכְנָסִים לֶאֱכֹל בִּתְרוּמָתָן, עַד סוֹף הָאַשְׁמוּרָה הָרִאשׁוֹנָה, דִּבְרֵי רַבִּי אֱלִיעֶזֶר. וַחֲכָמִים אוֹמְרִים, עַד חֲצוֹת. רַבָּן גַּמְלִיאֵל אוֹמֵר, עַד שֶׁיַּעֲלֶה עַמּוּד הַשָּׁחַר. מַעֲשֶׂה שֶׁבָּאוּ בָנָיו מִבֵּית הַמִּשְׁתֶּה, אָמְרוּ לוֹ, לֹא קָרִינוּ אֶת שְׁמַע. אָמַר לָהֶם, אִם לֹא עָלָה עַמּוּד הַשַּׁחַר, חַיָּבִין אַתֶּם לִקְרוֹת. וְלֹא זוֹ בִּלְבַד, אֶלָּא כָּל מַה שֶּׁאָמְרוּ חֲכָמִים עַד חֲצוֹת, מִצְוָתָן עַד שֶׁיַּעֲלֶה עַמּוּד הַשָּׁחַר. הֶקְטֵר חֲלָבִים וְאֵבָרִים, מִצְוָתָן עַד שֶׁיַּעֲלֶה עַמּוּד הַשָּׁחַר. וְכָל הַנֶּאֱכָלִים לְיוֹם אֶחָד, מִצְוָתָן עַד שֶׁיַּעֲלֶה עַמּוּד הַשָּׁחַר. אִם כֵּן, לָמָּה אָמְרוּ חֲכָמִים עַד חֲצוֹת, כְּדֵי לְהַרְחִיק אֶת הָאָדָם מִן הָעֲבֵרָה:

From when may one recite Shema in the evening? From the time when the Kohanim go in to eat their Terumah [produce consecrated for priestly consumption], until the end of the first watch – so says Rabbi Eliezer. And the Sages say: Until midnight. Rabban Gamliel says: Until the break of dawn. It once happened that his [Rabban Gamliel’s] sons came from a house of feasting. They said to him: We have not recited Shema. He said to them: If dawn has not broken, you are obligated to recite it. And [this is true] not only in this case; rather, in all cases where the Sages said that [some precept can be performed only] until midnight — their precepts are [still in force] until the break of dawn. [For example:] Burning the fats and limbs [of the sacrifices, on the Temple altar] — their precepts [can be performed] until the break of dawn. And [another example:] all [sacrifices] which may be eaten for one day — their precepts [of eating them can be performed] until the break of dawn. If that is so, why did the Sages say, "until midnight"? To distance a person from transgression.

Mishnah 2ב׳

מֵאֵימָתַי קוֹרִין אֶת שְׁמַע בְּשַׁחֲרִית. מִשֶּׁיַּכִּיר בֵּין תְּכֵלֶת לְלָבָן. רַבִּי אֱלִיעֶזֶר אוֹמֵר, בֵּין תְּכֵלֶת לְכַרְתִּי. וְגוֹמְרָהּ עַד הָנֵץ הַחַמָּה. רַבִּי יְהוֹשֻׁעַ אוֹמֵר, עַד שָׁלֹשׁ שָׁעוֹת, שֶׁכֵּן דֶּרֶךְ בְּנֵי מְלָכִים לַעֲמֹד בְּשָׁלֹשׁ שָׁעוֹת. הַקּוֹרֵא מִכָּאן וְאֵילָךְ לֹא הִפְסִיד, כְּאָדָם הַקּוֹרֵא בַתּוֹרָה:

From when may one recite Shema in the morning? From when one can distinguish between Tekhelet [purple-blue wool] and white. Rabbi Eliezer says: [The earliest time for Shema is when one can distinguish] between Tekhelet and the color of leek, and one must finish reciting it by sunrise. Rabbi Yehoshua says: [One may recite Shema] until three hours [of the day], for such is the way of the sons of kings, to arise at the third hour. If one recites [Shema] later than this, he has not lost out, [but rather is] like one who reads the Torah.