Exodus 29:4 - Coke's Commentary on the Holy Bible

And shalt wash them with water— The first thing to be done, in consecrating the priests, was to wash them all over with water; in token, no doubt, of that universal purity to which their sacred service obliged them. They were enjoined to wash their hands and feet every time they went into the tabernacle and ministered at the altar; see ch. Exodus 30:19-20 and compare John 13:10 with what has been observed upon ablution in our note on ch. Exodus 19:10.