(Lev. 19:2:) “You shall be holy.” R. Pinhas bar Hama the Priest said that R. Reuben said, “What is the meaning of that which is written (in Ezek. 3:12), ‘and I heard after me?’ I heard a great roaring sound. What is the meaning of ‘after me ('hry)?’ After ('hry) I and my friends praised Him, I heard the ministering angels, as they praised Him and said (ibid., cont.), ‘Blessed be the glory of the Lord from His place.’”
You should know that at the time that Moses went up above, he heard the voice of the angels praising like this. He [then] came down and taught Israel that they should say like this in a whisper, “Blessed be the name of His glorious majesty forever and ever.” R. Shmuel bar R. Nahmani said, “See what is written there (Ezekiel 1:25), ‘when they stood, their wings would droop.’ One who hears, ‘when they stood,’ would think there is sitting above.
But [in fact] it is all in standing, as stated (Is. 6:2), ‘Seraphs standing above Him.’ And so does it state (Dan. 7:16), ‘I approached one of those standing.’ And so too (I Kings 22:19), ‘I saw the Lord sitting on His throne and all the host of the heavens were standing over Him.’ And what is the meaning of ‘in their standing, their wings drooped?’
From when Israel praised [God], the wings of the ministering angels drooped, [meaning] they stopped (stood) from saying praise, as they say praise with their wings.” It also says (in Job 38:7), “When the morning stars (i.e., the seed of Jacob) sang together, all the children of God (i.e., all the angels) shouted for joy.”
R. Mani said, “Let not the recitation of the Shema be trivial in your eyes, because there are two hundred forty-eight words in it corresponding to [the number of] parts that are in a human being; and out of them [comes], ‘Blessed be the name of His glorious majesty forever and ever.’” The Holy One, blessed be He, said, “If you have kept what is Mine in reciting it properly, I will also keep what is yours.”
Therefore, David offered praise (in Ps. 17:8), “Keep me as the pupil of an eye.” The Holy One, blessed be He, said to him (in Prov. 4:4), “Keep My commandments and live.” R. Simeon ben Halafta said, “To what is the matter comparable? To someone who [lives] in the Galilee and has a vineyard in Judea, while someone in Judea has a vineyard in the Galilee.
The one who [lives] in the Galilee goes to Judea to cultivate his vineyard. The one in Judea goes to the Galilee to cultivate his vineyard. [One day] they meet with each another, and one said to the other, ‘Instead of you coming to my place, keep watch over what is mine in your area; and I will keep watch over what is yours in my area.’” So did David say (in Ps. 17:4), “Keep me as the pupil of an eye.”
The Holy One, blessed be He, said to him (in Prov. 4:4), “keep My commandments and live.” Similarly the Holy One, blessed be He, said to Israel, “Keep the commandment to recite the Shema morning and evening, and I will keep you.” So is it stated (in Ps. 121:7), “The Lord shall keep you from all evil; He shall keep your soul.”