Exodus 28-29 give lots of details of the proper attire (priestly garments & accessories) for Aaron and his sons as they serve the Lord as priests for the people. As 28:36 says, they are to be consecrated as "HOLY TO THE LORD" and to be anointed and ordained as ministers of the tabernacle according to all the ordinances given by God. God said, "So I will consecrate the Tent of Meeting and the alter and Aaron and his sons... then I will dwell among the Israelites and be their God... they will know that I am their God, who brought them out of Egypt so that I might dwell among them. I am the Lord their God."