Parsha Mitzvot: Tetzaveh: Mitzvah 99 – Concept 318
“You shall make vestments of sanctity for Aaron your brother, for glory and splendor.” (Exodus 28:2) The Cohanim must wear their priestly garments during service. (Rambam, Hilchot Klei Hamikdash V’Haovdim Bo – The Laws of the Temple Vessels and Employees)
Our Sages (Arachin 16) say that just as the sacrifices themselves were instruments of atonement for the Jewish people, so the priestly garments, when worn at the right time in the right place by the right people, were also instruments helping the Jewish people to achieve atonement.
This is the reason that the section dealing with the priestly garments was written right next to the section dealing with the sacrifices themselves. (Exodus 29:18)
The Breastplate would atone for sins committed erroneously by judges.
The Ephod would secure atonement for the sin of idolatry.
The Robe, called Mi’eil, secured atonement for loose use of one’s tongue.
The checkered tunic, Ketonet Tashbetz, secured atonement for blood spilled inadvertently. (Rabbeinu Bachya)