Leviticus 8:6

And Moses brought Aaron and his sons, and washed them with water.

Moses ... washed them with water. A summary account of this ceremony is given, Exodus 40:11. At consecration they were subjected to entire ablution, though on ordinary occasions they were required, before entering on their duties, only to wash their hands and feet. This symbolical ablution was designed to teach them the necessity of inward purity, and the imperative obligation on those who bore the vessels and conducted the services of the sanctuary to be holy.