Exodus 28:39-43

The tunic of fine linen shall be brocaded. The turban shall be made of fine linen. The sash shall be of variegated work. Likewise, for the glorious adornment of Aaron’s sons you shall have tunics and sashes and skullcaps made, for glorious splendor. With these you shall clothe your brother Aaron and his sons. Anoint and install them, consecrating them as my priests. You must also make linen pants for them, to cover their naked flesh from their loins to their thighs. Aaron and his sons shall wear them whenever they go into the tent of meeting or approach the altar to minister in the sanctuary, lest they incur guilt and die. This shall be a perpetual ordinance for him and for his descendants.