Aaron and his sons are to wear them when they enter the Tent of Meeting or when they approach the altar to serve in the Holy Place, so that they will not bring guilt on themselves and die. This is a law for Aaron and his descendants forever.
A man who has sex with his uncle's wife brings shame on his uncle. They will bear responsibility for their sin; they shall die without having children.
The priests must do as I demand, so that they don't become guilty and die because they have not done so, treating my requirements with contempt. I am the Lord who makes them holy.
But only you and your sons are responsible for your priesthood, doing all that concerns the altar and is behind the veil. Only you are to perform that service. I am giving you the gift of your priesthood, but anyone else who approaches the sanctuary must be executed.”
The camp of Moses, Aaron, and Aaron's sons was to the east of the Tabernacle, in the direction of the sunrise, in front of the Tent of Meeting. They were responsible for the sanctuary on behalf of the Israelites. Anyone else who tried to act as a priest was to be executed.