Midrash su Deuteronomio 8:10

(Exodus 13:3) "And Moses said to the people: Remember this day when you went out of Egypt, etc." I know only that the exodus from Egypt is mentioned in the daytime. Whence do I derive (the same for) the evenings? From (Devarim 16:3) "… so that you remember the day of your going out of Egypt all the days of your life": "the days of your life" — the days; "all the days of your life" — (to include) the nights, as per Ben Zoma. The sages say: "the days of your life" — in this world; "all the days of your life" — to include the days of the Messiah. Ben Zoma said to them: Israel is destined not to mention the exodus from Egypt in time to come, it being written (Jeremiah 23:7-8) "Therefore, behold, days are coming, says the L rd, when it will no more be said: 'As the L rd lives, who brought up the children of Israel from the land of Egypt, but as the L rd lives, who brought up and who brought the seed of the house of Israel from the land of the north.'" R. Nathan says: "who brought up and who brought": The exodus from Egypt is mentioned in time to come. And whence is it derived that we say "Blessed are You, O L rd our G d, and the G d of our fathers, the G d of Abraham, the G d of Isaac, and the G d of Jacob"? From (Exodus 3:15) "and G d said further to Moses: Thus shall you say to the children of Israel: The L rd, the G d of your fathers, the G d of Abraham, the G d of Isaac, and the G d of Jacob, sent me to you." And whence is grace over meals derived? From (Devarim 8:10) "and you shall eat and you shall be sated" — this is the first blessing. "for the land" — this is the second blessing. "the good" — this is "who builds Jerusalem," viz. (Ibid. 3:25) "the good land … and the Levanon." "that he gave you" — who gave all good to us (this is the blessing of "hatov vehametiv"). R. Chiyya b. Nachmani said in the name of R. Yishmael: It is already written (Ibid. 8:10) "and you shall eat and you shall be sated, etc." What would be lacking if it were not written "that He gave to you"? (It is written to signify that you must thank Him) both for His measure of good and for His measure of punishment. This tells me that a blessing is required after eating. Whence do I derive that it is required (also) before eating? R. Yishmael says: It follows a fortiori, viz.: If one who has eaten to satiety requires a blessing, how much more so, one who is hungry! R. Nathan says: It is written (I Samuel 9:13) "As soon as you enter the town, you will find him before he ascends the mount to eat; for the people will not eat until he comes, for he will first bless the offering, etc." R. Yitzchak says: It is written (Exodus 23:25) "And you shall serve the L rd your G d, and He will bless your bread and your water." When is it "your bread"? Before you have eaten it. This tells me only of food as requiring a blessing before it and after it. Whence do I derive (the same for) Torah? R. Yishmael says: It follows a fortiori, viz.: If food, which is only temporal, requires a blessing before and after it, how much more so Torah, which is eternal! R. Yehudah b. Betheira says: It is written (Devarim 8:10) "and you shall eat and you shall be sated and you shall bless … for the good land." What is lacking that "good" supplies? This ("good") is Torah, as it is written (Mishlei 4:2) "for a taking of 'good' have I given to you." R. Chanina, the son of the brother of R. Yehoshua says: It is written (Devarim 32:3) "When I call upon the name of the L rd" — the blesser; "give grandeur to our G d" — the answerers. And what do they answer? "Blessed is the L rd who is blessed forever." And when he mentions His name, they respond "Blessed is the name of the glory of His kingdom forever." And thus did David say (Psalms 34:4) "Exalt the L rd with me, and let us extol His name forever." Rebbi says (Mishlei 10:7) "the remembrance of the Tzaddik is for blessing": When he mentions the Tzaddik, "the Life of the worlds" — (Psalms 145:17) "the L rd is a tzaddik in all of His ways — let it be for blessing "Amen!"

(Ib. b) R. Avira expounded, sometimes speaking in the name of R. Ami, and at other times speaking in the name of R. Assi: The ministering angels said before the Holy One, Praised be He! "Sovereign of the universe, it is written in Thy Torah (Deu. 10, 17.) Who shows no favor to persons, and taketh no bribe. Behold Thou showest favors to Israel, for it is written (Num. 6. 26.) The Lord will show His favor unto thee." "Why shall I not favor Israel?" answered He, "for I wrote in my Torah which I gave to them (Deu. 8, 10.) And when thou hast eaten and are satisfied, then shalt thou bless. But they are so particular and careful that even if they eat only as much as the size of an olive or an egg, they also recite the after-meal grace."

(Fol. 21a) E. Juda said, "Whence do we learn that the after-meal grace is a Biblical law? It is written (Ib.) And when thou hast eaten and art satisfied, then shalt thou bless the Lord, thy God. Whence do we learn [that to say] the benediction before beginning the study of the Torah is a Biblical law? It is said (Deu. 32, 3.) When I call on the name of the Lord ascribe ye greatness unto our God."