Midrash su Esodo 28:29

The Rabbis say: The Holy One blessed be He said to Moses: ‘Go and appoint a High Priest for Me.’ [Moses] said before Him: ‘Master of the universe, from which tribe?’ He said to him: ‘From the tribe of Levi.’ [Moses asked:] ‘With what will I anoint him?’ He said to him: ‘With the anointing oil.’ At that moment, Moses was joyful; he said: ‘My tribe is so beloved before the Holy One blessed be He.’ The Holy One blessed be He said to him: ‘By your life, it is not your tribe, but it is your brother’ – that is what is written: “And you, bring [Aaron your brother] near to you” (Exodus 28:1). His anointing with the anointing oil, from where is it derived? It is as it is stated: “You shall take the anointing oil […and anoint him]” (Exodus 29:7). However, his service is not service and he has liability unless the names of the tribes are engraved on his heart, as it is written: “Aaron will bear the names…[of the children of Israel…upon his heart]” (Exodus 28:29). The Holy One blessed be He said: ‘The names of the tribes are dearer to me than the anointing oil with which priests and kings are anointed.’
Rabbi Neḥemya said: The Holy One blessed be He said to Moses: ‘Go and appoint a High Priest for Me.’ [Moses] said before Him: ‘Master of the universe, from which tribe?’ He said to him: ‘From the tribe of Levi.’ [Moses asked:] ‘With what will I anoint him?’ He said to him: ‘With the anointing oil.’ At that moment, Moses was joyful; he said: ‘My tribe is so beloved before the Holy One blessed be He.’ The Holy One blessed be He said to him: ‘By your life, it is not your tribe, but it is your brother; that is what is written: “And you, bring [Aaron your brother] near to you” (Exodus 28:1). His anointing with the anointing oil, from where is it derived? It is as it is stated: “You shall take the anointing oil […and anoint him]” (Exodus 29:7). However, his service is not service and he has liability unless the names of the tribes are engraved on his two shoulders, as it is written: “Aaron shall bear their names before the Lord upon his two shoulders as a remembrance” (Exodus 28:12). “Six of their names [on one stone and the names of the six that remain on the other stone]” (Exodus 28:10). Rav Beivai said: Had they been missing one letter they would not have served their purpose. Rabbi Oshaya taught: Even one dot.
Rabbi Shimon ben Yoḥai taught: There are three crowns; the crown of Torah, the crown of priesthood, and the crown of kingship. The crown of priesthood, Aaron merited it and took it. The crown of kingship, David merited it and took it. The crown of Torah is available for [all] generations. Anyone who acquires Torah it is as though he acquired [all] three of them. Anyone who did not acquire Torah, it is as though he did not acquire any of them.
Rabbi Bon said in the name of Rabbi Shmuel bar Naḥmani: We found that the Holy One blessed be He went a distance that takes five hundred years to traverse to make a name for Himself, as it is written: “[Who is like Your people, like Israel…] whom God went to redeem to Himself for a people and to make a name for Himself […nations and their gods]” (II Samuel 7:23). Rabbi Yosei HaGelili said: A nation and its gods.⁷He interprets the end of the verse to mean that God redeemed Israel despite the fact that there were idolaters among them who took their gods with them. Rabbi Akiva said to him: You have rendered the sacred profane. The Israelites said before the Holy One blessed be He: ‘You redeemed Yourself, as it were, as it is stated: “Whom You redeemed for Yourself from Egypt, nations and their God”’ (II Samuel 7:23).⁸According to Rabbi Yosei HaGelili, this would be translated as “their gods.” It is written: “Whom God went [halakh] [to redeem] for Himself [a people]” (I Chronicles 17:21), and later it says: “Whom God went [halekhu] [to redeem for Himself for a people]” (II Samuel 7:23). Halakh, this is the Holy One blessed be He; halekhu, this is Moses and Aaron.⁹The term halekhu is plural, and therefore the midrash interprets it as referring to Moses and Aaron. Thus, the verse means that Moses and Aaron were emissaries God sent to accomplish this objective.

(Lev. 9:1:) “And it came to pass on the eighth day.” This text is related (to Ps. 92:13), “The righteous one shall flourish (rt.: prh) like the palm….” This is Aaron, of whom it is stated (in Numb. 17:23), “[and there] the staff of Aaron of the House of Levi had sprouted (rt.: prh).” In the case of all the [other] trees, one plants them and they grow up by themselves (as single trees); but in the case of the palm, one plants it and it sends up sprouts on all sides. So it was in the case of Aaron. He planted and sprouts came up. These were Aaron's sons (i.e., according to I Chron. 6:35-36), “his son Eleazar, his son Phinehas, his son Abishua, [his son Bukki…].” (Ps. 92:13), “The righteous one shall flourish (rt.: prh) like the palm.” Where did he plant [them]? (Ps. 92:14), “[They are] planted in the house of the Lord.” (Lev. 8:33), “And you shall not go out from the door of the tent of meeting [for seven days].” It is therefore stated (in Lev. 9:1), “And it came to pass on the eighth day.” (Lev. 9:1), “And it came to pass on the eighth day Moses called [Aaron and his sons]….” Our masters have said: All seven days when Moses was at the thornbush, the Holy One, blessed be He, said to him, “Go on My mission”; but he was saying (in Exod. 4:13), “Please make someone else Your agent.” So was it the first and second day. The Holy One, blessed be He, said to him, “I say to you, ‘Go,’ and you say to Me, ‘Please make someone else Your agent?’ By your life, I am paying you back. Someday soon when that tabernacle is being made, you will be thinking privately that you should serve in the high priesthood; but I am telling you, ‘Call Aaron to serve.’” It is therefore stated (in Lev. 9:1), “Moses called Aaron and his sons.” There is a calling which is for abundance [and there is] a calling for famine. Where is it shown [that there is a calling] for abundance? Where it is stated (in Ezek. 36:29), “I will call for the grain and increase it.” And where is it shown [that there is a calling] for famine? [Where it is stated (in II Kings 8:1),] “for the Lord has called for a famine… [for seven years].” There is a calling for greatness, as stated (in Lev. 9:1), “Moses called [Aaron].” Moses said to him, “The Holy One, blessed be He, has told me to ordain you as high priest.” Aaron said to him, “You have labored on the tabernacle; so shall I be made high priest?” He said to him, “By your life, even though you are being made high priest, it is as if I were being made [high priest];¹¹See above, Exod. 1:24. for just as you were glad for me in my greatness, so I am glad for you in your greatness.” Now when was he glad for him? When the Holy One, blessed be He, said to him (in Exod. 3:10), “So come now, I will send you unto Pharaoh.” The Holy One, blessed be He, said to him, “Go, keep this commandment.” Moses said to Him (in Exod. 4:10, 13), “Pray (bi) – Lord, You are doing me wrong. My brother is older than I; yet I am going ahead of him.” The Holy One, blessed be He, said to him, “[By your life], you have spoken rightly; nevertheless (according to Exod. 4:14), when he sees you, he will be glad in his heart.” R. Simeon ben Yohay said, “The Holy One, blessed be He, said to him, ‘That heart which is glad for his brother's greatness shall have those precious stones (of Exod. 28:17-21) laid upon it.’” Therefore, all those seven days that Moses was busy in the tabernacle, he was sprinkling the blood and performing the sacrificial burning of the choice pieces. The Holy One, blessed be He, said to them, “What do you think? That you are high priest? Call your brother so that he may serve as high priest.” Ergo (in Lev. 9:1), “And it came to pass on the eighth day Moses called [Aaron and his sons, and the elders of Israel].” Why the elders of Israel? In order to promote him in the presence of the elders. The Holy One, blessed be He, said to him, “Call the elders and ordain him in their presence, lest they say that he became high priest on his own.

6) Why is "linen" mentioned four times (in this verse)? To exclude four garments in respect to which it is written "before the L–rd." Because it is written of the choshen (the breastplate) (Shemoth 28:29) "And Aaron shall bear the names of the children of Israel in the choshen of judgment upon his heart when he comes into the holy place as a remembrance before the L–rd always," I might think that he could enter with it (even) into the holy of holies"; it is, therefore, written "linen" — and not with the choshen.