Midrash su Salmi 102:1

(Fol. 26b) We are taught (in a Memera)' that R. Jose the son of R. Chanina said: "The daily services were ordained by the Patriarchs (Abraham, Isaac and Jacob)." R. Joshua b. Levi said: "The daily services were ordained to correspond with the [two] perpetual-daily-offerings." We have a Baraitha coinciding with the opinion of R. Jose, the son of R. Chanina, and we have also a Baraitha coinciding with the opinion of R. Joshua b. Levi. As to the support of R. Jose we are taught, "Abraham ordained the morning service, as it is said (Gen. 19, 27.) And Abraham rose up early in the morning to the place where he had stood before the Lord. Omad (stood) refers to nothing else but prayer; for it is said (Ps. 106, 30.) Then stood up (Vaya'amod) Phinehas and offered a prayer. Isaac ordained the afternoon service (Mincha), for it is said (Gen. 24, 63.) And Isaac went out 'Lasuach' in the field towards evening. By the word Lasuach is meant prayer, for it is said (Ps. 102, 1.) A prayer of the afflicted when he is overwhelmed and poureth out before the Lord his complaint (Sicho). Jacob ordained the evening service (Ma'arib), for it is said (Gen. 28, 11.) Vayifg'a upon a certain place, and tarried there all night; by the word Vayifg'a, prayer is meant, for it is said (Jer. 7, 16.) But thou — pray not thou in behalf of this people, nor lift up entreaty or prayer in their behalf, nor make intercession to me (Tifga)." We are taught, coinciding with the opinion of R. Joshua b. Levi: "Why did [the Rabbis] say that the time for the morning service is until noon? Because the perpetual-daily-morning-offering had also its time limited to noon. R. Juda says: Until the fourth hour of the day."

And God Almighty give you mercy before the man (Gen. 43:14). May it please our master to teach us the number of times a man must pray each day. Thus did our masters teach us: A man must not pray more than three times each day, as instituted by the patriarchs of the world. Abraham established the morning prayer, as it is said: And Abraham got up early in the morning to the place where he had stood before the Lord (Gen. 19:27). The word stood refers only to prayer, as is said: Then stood up Phinehas, and prayed (Ps. 106:30). Isaac instituted the afternoon prayer, as it is said: And Isaac went out to meditate in the field (Gen. 24:63). The word meditation is used with reference to prayer, as it is said: A prayer of the afflicted when he fainteth, and poureth out his meditation for the Lord (Ps. 102:6). Jacob introduced the evening prayer, as it is said: And he lighted upon the place (Gen. 28:11). The word vayifgah (“lighted upon”) alludes to prayer, as is said: Therefore, pray not thou … neither make intercession (tifga) (Jer. 7:16). And it is written concerning Daniel: And he kneeled upon his knees three times a day, and prayed (Dan. 6:11). However, in this verse, the time of prayer is not specified. It was David who came and set the time for prayer, by saying; Evening, and morning, and at noonday, will I complain and moan, and He hath heard my voice (Ps. 55:18). Therefore a man may not pray more than three times a day.

(Gen. 43:14:) AND³⁵Sections 11, 12, and 13 are missing from Buber’s Oxford MS and are added by Buber from Codex Vaticanus Ebr. 34. MAY GOD ALMIGHTY GRANT YOU MERCY. Let our master instruct us: How many Tefillot³⁶The Tefillah, also called the Eighteen Benedictions or the ‘Amidah, forms the central intercession of the Jewish liturgy. is one obligated to pray in a day?³⁷Tanh., Gen. 10:9. Thus have our masters taught: One does not pray more than the three Tefillot which the ancestors of the world instituted.³⁸Ber. 26b (bar.); yBer. 4:1 (7a); cf. Ber. 4:1; Abraham instituted the morning Tefillah, as stated (in Gen. 19:27): NOW ABRAHAM WENT EARLY IN THE MORNING UNTO THE PLACE WHERE HE HAD STOOD ('MD) BEFORE THE LORD. Isaac instituted the Tefillah of the minhah (the Tefillah in the afternoon), as stated (in Gen. 24:63): NOW ISAAC WENT OUT TO BOW DOWN (rt.: SWH) IN THE FIELD TOWARD EVENING. Jacob instituted the evening Tefillah, as stated (in Gen. 28:11): WHEN HE CAME (rt.: PG')³⁹The parallel text in the traditional Tanhuma (Gen. 10:9) explains that ‘MD, SWH, and PG‘ all denote prayer and finds the evidence in Ps. 106:30, Ps. 102:1, and Jer. 7:16 respectively. TO A CERTAIN PLACE.⁴⁰See Acts 10:9. Now it is also written about Daniel (in Dan. 6:11): AND THREE TIMES A DAY [HE KNELT ON HIS KNEES]. But < the text > did not explain at what hour. David came and explained (in Ps. 55:18 [17]): EVENING, MORNING, AND NOON < I COMPLAIN AND MOAN; AND HE HEARS MY VOICE >. Therefore, one is not authorized to pray more than three Tefillot in a day.⁴¹TBer. 3:8; Ber. 31a; see yBer. 4:1 (7a). But R. Johanan said: And would that one might go on praying all day long!⁴²Cf. Deut. R. 2:1 and M. Sam. 2, which argue against reciting the three services at one time. Antoninus asked Our Holy Rabbi: Is it permitted to pray at every hour? He said to him: It is forbidden. He said to him: Why? He said to him: Lest you treat the Most High with frivolity. He did not accept < this answer > from him. What did he do? He went to him early in the morning. He said to him: Greetings, Lord.⁴³Gk.: Kyrie chaire. An hour later he came in to him. He said to him: {'MNH RTWQ} [Imperator]!⁴⁴The Latin word originally designated a general, but in imperial times imperator became the title of Roman emperors. Buber has taken this reading from the traditional Tanhuma because he can make no sense of his manuscript, which reads: ’MNH RTWQ. An hour later he < again > said to him: Shalom to you, O King. He said to him: Why are you being disrespectful to the monarchy? He said to him: Let your ears hear what you are putting forth from your mouth. If you, who are flesh and blood, say this in the case of someone who asks after you every hour, how much the more so in the case of one who is disrespectful to the Supreme King of Kings, the Holy One. Thus one should not bother him all the time.