From which time may the Shema be recited in the evenings? From the time that the Cohanim have gone in to eat their terumah [Cohanim who became unclean and who immersed may not eat terumah until "their sun has set"; that is, until the stars have appeared. The reason "From the time the stars have appeared" is not stated is that we might thereby be apprised of an incidental learning, viz., if the Cohanim become defiled with the type of uncleanliness where their cleansing entails an offering (such as zav or metzora), the want of this expiatory offering does not prevent them from eating terumah, it being written (Leviticus 22:7): "And when the sun has set vetaher ('and the day has ended'), he may eat of the holy things" — the setting of the sun is a prerequisite for his eating terumah, but his expiatory offering is not], until the end of the first watch. [the first third of the night, the night being divided into three watches. From that point on, it is not considered the time of the recital of the Shema of reclining, and it does not satisfy (Deuteronomy 6:7): "…when you lie down." And before the stars come out, too, it is daytime, and not the time of lying down. And those who are beforehand and recite the evening Shema while it is still day, rely in this on R. Yehudah, who says (26a) that the Minchah prayer may be recited until midway through the afternoon, an hour and a quarter before the night. And it is ruled that one may follow R. Yehudah in this regard — that immediately upon the expiration of the time for the Minchah prayer, the time for the recital of the evening Shema begins.] These are the words of R. Eliezer. And the sages say: Until midnight. R. Gamliel says: Until the appearance of the morning star. [For the entire night is considered the time of lying down. And the halachah is in accordance with R. Gamliel, the sages, too, agreeing with him, having said "Until midnight" only to keep one far from transgression. However, ab initio, when the time of the recital of Shema of the Mishnah arrives —- that is, when the stars appear — one is forbidden to repast, and, it goes without saying, to sleep, until he recites the Shema and prays.] It once happened that his sons came late from a feast [The sons of R. Gamliel heard that the sages had said: "Until midnight," and this is what they said to him: Do the sages differ from you, saying: "Until midnight," specifically, and not afterwards? (and "one against many, the halachah is according to the many"), or do the sages hold with you, but say "until midnight" to keep one far from transgression? And he answered: The sages hold with me, and say: "Until midnight" to keep one far from transgression; and you are obliged to recite it.], and they said to him: We did not yet recite the Shema. He told them: If the morning star has not yet appeared, it is incumbent upon you to recite it. And not this alone [(This is still R. Gamliel speaking to his sons)] did they say, but wherever the sages say "until midnight," the mitzvah obtains until the appearance of the morning star. The mitzvah of burning the fats [of the offerings] and the pieces [of the daily afternoon burnt-offering — It is a mitzvah to offer up the pieces the entire night, viz. (Leviticus 6:2): "It is the burnt-offering upon its firewood on the altar all the night until the morning."] obtains until the appearance of the morning star. And the mitzvah of eating all of those offerings which must be eaten in one day [such as a thank-offering, a sin-offering, a guilt-offering, and the like, which are eaten a day and a night — the time for eating them is until the appearance of the morning star; and it is that which brings them to the status of nothar (left beyond the designated time and requiring to be burned)], ("the mitzvah, etc.") obtains until the appearance of the morning star. If so, why did the sages say: "Until midnight"? [in respect to the recital of the Shema and the eating of offerings. But they did not say "until midnight" at all in respect to the burning of the fats and the pieces, having mentioned this here only to apprise us that the mitzvah of all things designated for the night obtains the entire night.] To keep one far from transgression. [that he not come to eat them after the appearance of the morning star and incur kareth ("cutting-off"); and, similarly, with the recital of the Shema, that he not say "I still have time" and miss the designated time].

It has been reported : R. Jose b. R. Hannina said : The Patriarchs instituted the Tefillot. R. Joshua b. Levi said: The Tefillot were instituted to correspond with the continual sacrifices. There is a teaching in agreement with both of them. There is a teaching in agreement with R. Jose b. R. Hannina: Abraham instituted the morning Tefillah; as it is said, "And Abraham got up early in the morning to the place where he had stood" (Gen. xix. 27) — "standing" means prayer; as it is said, "Then stood up Phineas and prayed" (Ps. cvi. 30). Isaac instituted the afternoon Tefillah; as it is said, "And Isaac went out to meditate in the field at eventide" (Gen. xxiv. 63) — "meditation" [sihah] means prayer; as it is said, "A prayer of the afflicted when he fainteth, and poureth out his complaint [sihah] before the Lord" (Ps, cii. 1). Jacob instituted the evening Tefillah ; as it is said, "And he lighted [paga'] upon the place, and tarried there all night" (Gen. xxviii. 11) — "alighting" means prayer; as it is said, "Therefore pray not thou for this people, neither lift up cry nor prayer for them, neither make intercession [paga'] to Me" (Jer. vii. 16).

HEAR, O ISRAEL: THE LORD IS OUR GOD, THE LORD IS ONE. And thou shalt love the LORD thy God with all thy heart, and with all thy soul, and with all thy might. And these words, which I command thee this day, shall be upon thy heart; and thou shalt teach them diligently unto thy children, and shalt talk of them when thou sittest in thy house, and when thou walkest by the way, and when thou liest down, and when thou risest up. And thou shalt bind them for a sign upon thy hand, and they shall be for frontlets between thine eyes. And thou shalt write them upon the door-posts of thy house, and upon thy gates.

Along the same lines, Rabbi Yoḥanan said in the name of Rabbi Yosei: From where is it derived that the Holy One, Blessed be He, prays? As it is stated: “I will bring them to My holy mountain, and make them joyful in the house of My prayer” (Isaiah 56:7). The verse does not say the house of their prayer, but rather, “the house of My prayer”; from here we see that the Holy One, Blessed be He, prays. The Gemara asks: What does God pray? To whom does God pray? Rav Zutra bar Tovia said that Rav said:
God says: May it be My will that My mercy will overcome My anger towards Israel for their transgressions,
and may My mercy prevail over My other attributes through which Israel is punished,
and may I conduct myself toward My children, Israel, with the attribute of mercy,
and may I enter before them beyond the letter of the law. Similarly, it was taught in a baraita that Rabbi Yishmael ben Elisha, the High Priest, said: Once, on Yom Kippur, I entered the innermost sanctum, the Holy of Holies, to offer incense, and in a vision I saw Akatriel Ya, the Lord of Hosts, one of the names of God expressing His ultimate authority, seated upon a high and exalted throne (see Isaiah 6).
And He said to me: Yishmael, My son, bless Me.
I said to Him the prayer that God prays: “May it be Your will that Your mercy overcome Your anger,
and may Your mercy prevail over Your other attributes,
and may You act toward Your children with the attribute of mercy,
and may You enter before them beyond the letter of the law.”
The Holy One, Blessed be He, nodded His head and accepted the blessing. This event teaches us that you should not take the blessing of an ordinary person lightly. If God asked for and accepted a man’s blessing, all the more so that a man must value the blessing of another man.