The Kohen Gadol and His Vestments

THE KOHEN GADOL AND HIS VESTMENTS

Yahweh's covenant with Aaron, Yahweh's first High Priest of the Old Covenant: He made an everlasting covenant with him, and gave him the priesthood of the people. He adorned him with impressive vestments, he dressed him in a robe of glory.
Sirach 45:7

For the glorious adornment of your brother Aaron you shall have sacred vestments made
Exodus 28:1-43

The Kesones [Tunic]: made of white linen, woven all of one piece with a boxlike knit.
The Me'il [ Robe]: made of turquoise wool. The Hem of the Me'il was of alternating pomegranates and bells. The pomegranates were of turquoise, purple, and scarlet wool and they were alternated with gold bells.
The Girdle or sash of variegated work
The Tzitz [Head-plate]: made of pure gold, inscribed with the words "Holy to Yahweh", and tied with a turquoise blue wool cord.
The Ephod: garment with shoulder straps and stones on the shoulders [avnei shoham stones] with the engraved names of the sons of Israel according to birth order, six on each shoulder, with a tie belt made of gold, turquoise, purple, and scarlet wool and twisted linen.
The Choshen [Breastplate], the breastplate of judgment: a folded pocket worn on the breast with 12 stones in 4 rows of 3, one stone for each of the 12 Tribes of Israel engraved with the name of each tribe and in which the Urim and Tumim [Thummim] are carried. The Chosen [Breastplate] is attached on to the Ephod with straps/ties
The Turban/ Mitre: [with embroidered sash]
The Linen Breeches: that went from the hips to the thighs

Sirach [Ecclesiasticus] 45:1-22 recalls God's covenant with Aaron for a perpetual ministerial priesthood and outlines the duties of the priesthood in 45:15-17; the passage reads: Moses consecrated him and anointed him with holy oil; and this was an everlasting covenant for him, and for his descendants as long as the heavens endure, that he should preside over worship, act as priest, and bless the people in the name of the Lord. He chose him out of all the living to offer sacrifices to the Lord, incense and perfume as a memorial to make expiation for the people. He entrusted him with his commandments, committed him to the statues of the Law for him to teach Jacob and his decrees and enlighten Israel on his law. [New Jerusalem translation].

Question: In this passage from Sirach [Ecclesiasticus], what four elements identify the office of the priesthood of God's covenant with Israel?
Answer:

His dignity and responsibility as God's representative
The purpose of the spiritual side of his priestly mission which is to act on behalf of the covenant people in their relationship with God, instructing them in the Law of God and in living lives of holiness
The purpose of priestly service to God and the people in the liturgy of covenant worship
To offer sacrifice for the atonement of sin and the restoration of communion with God