“And you shall make for them linene trousers to cover their nakedness and they shall reach from the waist to the thighs. They shall be on Aaron and on his sons when they come into the tabernacle of meeting, or when they come to the altar to minister in the holy place, that they do not incur iniquity and die. It shall be a statue forever to him and his descendants after him.”
– Exodus 28:42-43
Commentary
Apparently based on this abounas, and possibly the deacons, must wear boxers not briefs to pray the liturgy
Not So Spiritual Words 