Midrash su Deuteronomio 6:9

(Exod. 27:20:) AND YOU SHALL COMMAND THE CHILDREN OF ISRAEL…. This text is related (to Cant. 1:15): AH, YOU ARE BEAUTIFUL, MY BELOVED…. R. Aqiva said: All of the whole world and its fullness was not as worthy as the day on which the Torah of Song of Songs was given to Israel; for while all of the writings are holy, the Song of Songs is the holiest of the holy.¹Yad. 3:5; Tanh., Exod. 8:1; Cant. R. 1:1:11. R. Eleazar ben Azariah said: To what is the matter comparable? To a king who took a se'ah of wheat and gave it to a baker. He said to him: Take from it so much fine flour, so much crushed grain, so much bran. Similarly all the Writings are holy, but the Song of Songs is the holiest of the holy. Rabbi said: See how the Holy One praises the assembly of Israel in it (i.e., in Cant. 1:15). AH, YOU ARE BEAUTIFUL, MY BELOVED. AH, YOU ARE BEAUTIFUL in works.²Cf. Cant. R. 1:15:1. AH, YOU ARE BEAUTIFUL in the work of your ancestors. AH, YOU ARE BEAUTIFUL in the house. AH, YOU ARE BEAUTIFUL in the field. In the house (according to Deut. 6:9): UPON THE DOORPOSTS OF YOUR HOUSE. In the field through priestly shares, tithes, gleaning the forgotten sheaf (of Deut. 24:19), and through the pe'ah (of Lev. 19:9). (Cant. 1:15:) AH, YOU ARE BEAUTIFUL on the roof (according to Deut. 22:8): YOU SHALL MAKE A PARAPET FOR YOUR ROOF. (Cant. 1:15:) AH, YOU ARE BEAUTIFUL in this world. AH, YOU ARE BEAUTIFUL in the world to come.

R. Mair was accustomed to say that a man is bound to repeat a hundred blessings every day, as it is said (Deut. 10, 12) And now, Israel, what doth the Lord thy God require of thee. (Fol. 44) R. Shesheth said: "He who neglects to wear Tephilin (phylacteries) [every week-day], transgresses eight positive commandments; he who has no fringes on his garment transgresses five positive commandments. Any priest, who does not ascend [the stand] to pronounce the benediction transgresses three positive commandments. He who has no Mezuzah on his door-post transgresses two positive commandments, for the repeated word and ye shall write (Deut. 6,9; 11,20)." Resh Lakish said: "He who does not neglect to lay [every day] Tephilin will live long, as it is said (Is. 38, 16) O Lord, hy these things men live, and altogether therein is the life of my spirit. Wherefor recover Thou me, and make me to live."

“His left is under my head and his right embraces me” (Song of Songs 2:6).
“His left is under my head,” these are the first tablets; “and his right embraces me,” these are the second tablets. Alternatively, “his left is under my head,” these are ritual fringes; “and his right embraces me,” these are phylacteries. Alternatively, “his left is under my head” this is the reciting of Shema; and his right embraces me,” this is the Amida prayer. Alternatively, “his left is under my head,” this is sukka; “and his right embraces me,” this is the cloud of the Divine Presence in the future. That is what is written: “The sun will no longer be for you the light of day and the glow of the moon will not illuminate for you” (Isaiah 60:19). Who illuminates for you? “The Lord will be for you an eternal light” (Isaiah 60:19). Alternatively, “his left is under my head,” this is mezuza.” Rabbi Shimon ben Yoḥai taught: “You shall write them on the doorposts of your house” (Deuteronomy 6:9), when you enter from the marketplace to your house.⁷⁷It is on the right of the person entering the house, which is the left of the person exiting.
Rabbi Yoḥanan said: It is written: “You shall position the table outside the curtain [and the candelabrum opposite the table, on the side of the Tabernacle toward the south; and you shall put the table on the north side]” (Exodus 26:35).⁷⁸Since the Divine Presence emanated from the Holy of Holies, the candelabrum was to its right and the table was to its left. But that is not the case; a person places a candelabrum on the left so it will not restrict the right. A person does not place the left under the head and embrace with the right.⁷⁹The unusual placement of the candelabrum and the table reflect the fact that God’s embrace of Israel is not, as it were, for His comfort, but rather in order to support them (Midrash HaMevoar; cf. Matnot Kehuna).
Rabbi Aḥa said: Rabbi Yoḥanan cites it from this verse: “To love the Lord your God…and to cleave to Him” (Deuteronomy 30:20). What is this cleaving? “His left is under my head.”