Aaron the priest is dressed in holy garments of glory and beauty (Exodus 28:2). So are his sons: They have tunics, sashes, and caps “for glory and for beauty” (Exodus 28:40). Yahweh pours glory on the head of Aaron, but it runs down on his beard, down to the skirts of his garments, down to his sons, who are his helpers in the Edenic tabernacle.

The vestments of Aaron’s sons are simpler than Aaron’s. They don’t wear an ephod, or a breastplate, or onyx stones on the shoulders - only tunics, sashes, and caps. More importantly, the garments of Aaron’s sons aren’t “holy.” Aaron’s sons are “consecrated” by the ritual of “filling the hand” (Exodus 28:41), but their holiness isn’t the same level as their father’s. Aaron, and all subsequent high priests, have a higher status than the rest of the priests, and their vestments are likewise more intensely sacred. 

Verses 42-43 describe one last item of clothing, linen breeches to cover their “naked flesh” (v. 42). Both Aaron and his sons wear this underwear when they enter the tent or approach the altar (v. 43). It is treated with great solemnity: “A statute forever to [Aaron] and his seed after him” (v. 43). It’s the only item of clothing described in these terms.

The structure of the chapter reinforces its importance. These “breeches” occupy a surprisingly prominent place in the chapter. After describing all the exterior glory of Aaron, vestments that make him a representative of Israel, a sin-bearer, a living tabernacle, an oracle, Yahweh ends the instructions with a reminder to put on underpants. 

Why does this item of clothing come at the end of the chapter? Why is it given so much prominence?

First, its place in the chapter fits with the overall flow, which moves from the most visible and exterior garments to the inner ones. Given the parallels between the priestly garments and the tabernacle, this movement suggests an entry into the holy environment. As a priest would move from the court to the holy place to the most holy place, so the chapter moves from ephod and breastplate to the robe to the undergarments. That hints at a link between the covering of Aaron’s flesh and the covering of the Most Holy Place.

Second, the requirement has an Edenic background. Adam and Eve were placed in the original garden sanctuary. Once they sinned, they covered their flesh with fig leaves, knowing that they could no longer stand naked in Yahweh’s presence. Aaron and his sons also cover their flesh with a vegetable-based garment, breeches made of linen. 

Third, that Edenic background reminds us, if we needed reminder, that “flesh” has a specific meaning in Scripture and in the tabernacle system particularly. It refers to the sexual organs (as it does in Leviticus 15, for instance). Aaron’s penis and scrotum have to be covered when he enters the Lord’s presence. As in Eden, the “flesh” is somehow the locus of shame and sin. Aaron’s flesh has already been cut and removed in circumcision, but even his circumcised flesh can’t be shown in the tabernacle. Leviticus 18 and 20 are concerned with other forms of illicit uncovering. Uncovering nakedness is reserved for the marriage bed, when both man and wife are covered with one covering. Naked flesh isn’t to be seen in the tabernacle.

Fourth, this rule eliminates certain forms of ancient pagan religious practice. Sexual acts were often part of fertility rites in the ancient world. By covering their naked flesh, Aaron and his sons confess Israel’s faith that Yahweh is the source of fecund life. They are called to walk by faith in His potency, not by confidence in their own.