Exodus 30:17-21 (KJV)
17 And the LORD spake unto Moses, saying, 18 Thou shalt also make a laver of brass, and his foot also of brass, to wash withal: and thou shalt put it between the tabernacle of the congregation and the altar, and thou shalt put water therein. 19 For Aaron and his sons shall wash their hands and their feet thereat: 20 When they go into the tabernacle of the congregation, they shall wash with water, that they die not; or when they come near to the altar to minister, to burn offering made by fire unto the LORD: 21 So they shall wash their hands and their feet, that they die not: and it shall be a statute for ever to them, even to him and to his seed throughout their generations.
The book of Exodus makes several references to Aaron to wash with water when appearing before the Lord.Could this be in a physical or spiritual sense, the author of Hebrews uses the same word but in reference to baptism
Hebrews 6:1-2 (KJV)
1 Therefore leaving the principles of the doctrine of Christ, let us go on unto perfection; not laying again the foundation of repentance from dead works, and of faith toward God, 2 Of the doctrine of baptisms, and of laying on of hands, and of resurrection of the dead, and of eternal judgment