Midrash su Deuteronomio 33:9

R. Juda, in the name of Samuel, said: "The tribe of Levi did not worship idols [the golden calf], as it is said (Ex. 32, 26) And Moses stationed himself at the gate of the camp, and said: Whoever is on the Lord's side, let him come unto me. And there assembled themselves unto him, all the sons of Levi." Rabina was sitting and repeating this tradition, whereupon the children of R. Papa b. Abba raised the following objection: (Deut. 33, 9) [The tribe of Levi] which said [in the golden calf incident] of its father and its mother I have not seen Mm, [hence some of the tribe of Levi did worship the idol]. Rabina explained: "Father, refers to the maternal grandfather, who was of Israel; brother, refers to a half-brother of the mother; and children, to the daughter's children, whose father was an Israelite."

“The sentries patrolling the city found me, they struck me, they wounded me; the guards of the walls took my mantle from upon me” (Song of Songs 5:7).
“The sentries patrolling the city found me” – these are “Tatenai, the governor of Avar Nahara” (Ezra 5:3) and his associates.³¹They demanded to know who had allowed the Jews to rebuild the Temple. “They struck me, they wounded me” – “they wrote an accusation against the inhabitants of Judah and Jerusalem” (Ezra 4:6). “The guards of the walls took my mantle from upon me” – the walls of Jerusalem.³²The guards of the walls of Jerusalem, namely the Jews who were rebuilding the walls, “took my mantle” in that they rebuilt the walls in a less impressive manner than the manner in which the walls had originally been built. Rabbi Abba bar Kahana said: In the past, the wall was built with stones of eight cubits and stones of ten cubits.³³See I Kings 7:10. However, here: “It is built with great [gelal] stones” (Ezra 5:8), stones that are rolled [degilgul].³⁴They were too heavy to carry, but could be rolled. By contrast, the stones in the past were much larger and could not even be rolled.
Another matter: “The sentries…found me” – the tribe of Levi,³⁵This was when the Levites were mobilized by Moses to punish those who worshipped the Golden Calf (Exodus 32:26). in whose regard it is written: “For they observed Your word” (Deuteronomy 33:9). “Patrolling the city” – just as it says: “Pass back and forth from gate to gate” (Exodus 32:27). They struck me, they wounded me” – just as it says: “Each man slay his brother” (Exodus 32:27). They “took my mantle from upon me” – this is weaponry. Rabbi Shimon ben Yoḥai says: The weapon that was given to Israel at Ḥorev, the ineffable name was etched upon it. When they sinned it was taken from them. How was it taken? Rabbi Aivu said: It was peeled on its own. The Rabbis say: An angel descended and peeled it. “Guards of the walls,” [these are] the guards of the walls of Torah.³⁶The Levites served as teachers of Torah and as sages who enacted decrees to safeguard observance of the Torah.

(Numb. 8:6:) “Take the Levites.” This text is related (to Ps. 11:5), “The Lord tests the righteous.” The Holy One, blessed be He, does not elevate a person to an office until He first tests and examines him.¹Numb. R. 15:12. When he withstands his test, He elevates him to the office. And so you find in the case of our father Abraham; when the Holy One, blessed be He, tested him with ten temptations, he withstood his trials. Then after that He blessed him, as stated (in Gen. 24:1), “And the Lord blessed Abraham in all things.” So also in the case of Isaac, when He tested him with the days of Abimelech, he withstood the trial. Then after that He blessed him, as stated (in Gen. 26:12), “So Isaac sowed on that land […] for the Lord had blessed him.” So also in the case of Jacob, when He tested him by means of all those tribulations with Esau, with Rachel, with Dinah, with Joseph, with Simeon, with Benjamin and [with the tribulation of] how he departed from the house of his father and his mother (in Gen. 32:11), “for with [only] my staff did I cross [this Jordan].” Then after that He blessed him. It is so stated (in Gen. 35:9), “Now God appeared unto Jacob again, when he came from Paddan-Aram, and blessed him.” So also in the case of Joseph, He tested him with all of those tribulations, with the wife of Potiphar and he was imprisoned for twelve years. Then after that he came out and became king because he had withstood his trial. Ergo (in Ps. 11:5), “The Lord tests the righteous.” So also in the case of the tribe of Levi, they laid down their lives for the sanctification of the name of the Holy One, blessed be He, (i.e. for martyrdom), so that the Torah would not be set aside. Now when Israel was in Egypt, they had rejected the Torah and circumcision and all of them had become worshipers of idols, as Ezekiel has demonstrated where it is stated (in Ezek. 20:5), “And you shall say unto them, ‘Thus says the Lord God, “In the day that I chose Israel […].”’” Then what is written at the end (in vs. 8)? “But they rebelled against Me and did not come to hearken unto Me; each man did not cast away [the abominations of their eyes nor did they forsake the idols of Egypt].” What did the Holy One, blessed be He, do? He brought darkness upon Egypt for three days, and during those [days] he killed all the wicked ones of Israel. For this reason it says (in Ezek. 20:36-38), “[As I brought your ancestors to judgment in the desert of the land of Egypt….] So will I remove from you those who rebel and transgress against Me.” So also it says (in Cant. 2:13), “And the fig tree sheds²Heb.: hanetah. Although the biblical context suggests a translation such as “puts forth” or “ripens” the context understands this rare verb in a more negative sense. See above vol. 2, p. 62 Tanh. (Buber); Exod. 3:7). its green figs…,” these are the wicked who are in Israel; (ibid. cont.) “and the vines in blossom give off fragrance,” these are the rest who have repented and been accepted; (ibid. cont.) “arise, my beloved, my fair one, and come away,” for behold the time of redemption has arrived. However all those in the tribe of Levi were righteous and carried out the Torah. It is so stated (in Deut. 33:9), “For they observed Your word,” i.e., the Torah; (ibid. cont.) “and kept Your covenant,” i.e., circumcision. And not only that, but when Israel made the calf, the tribe of Levi did not participate there, as stated (in Exod. 32:26), “So Moses stood up on the gate of the camp and said, ‘Whoever is for the Lord come to me,’ and all the Children of Levi gathered unto him.” When Moses said (in vs. 27), “Each [of you] put his sword on his thigh…,” they immediately did so. Moreover they did not show partiality. And so Moses blesses them, [namely (according Deut. 33:9)], “The one who says of his father and mother, ‘I do not consider them’ and his brother….” When the Holy One, blessed be He, saw that they all were righteous, that He had tested them and they had withstood their trial – as stated (of Levi in Deut. 33:8), “[Your faithful one,] whom You tested at Massah” – the Holy One, blessed be He, immediately said (in Numb. 8:14), “And the Levites shall belong to Me,” to fulfill what is stated (in Ps. 11:5), “The Lord tests the righteous.” In the case of the wicked, however, it is written of them (ibid. cont.), “but His soul (i.e. The soul of the Holy One, blessed be He,) hates the wicked and the lover of injustice.” David said (in Ps. 128:1), “Fortunate is everyone who fears the Lord and walks in His ways.”