Albert Barnes Commentary Leviticus 8:6

"And Moses brought Aaron and his sons, and washed them with water." — Leviticus 8:6 (ASV)

Washed them with water - Moses caused them to bathe entirely , not merely to wash their hands and feet, as they were to do in their daily ministrations. See the marginal reference. This bathing, which the high priest had also to go through on the day of atonement, was symbolic of the spiritual cleansing required of all (2 Corinthians 7:1), but especially of those who had to draw near to God to make reconciliation for the sins of the people (Hebrews 7:26; Matthew 3:15).