"No man of the descendants of Aaron, who is a leper or who has a discharge, may eat of the holy gifts until he is clean. And if one touches anything made unclean by a corpse or if a man has a seminal emission, or if a man touches any teeming things by which he is made unclean, or any man by whom he is made unclean, whatever his uncleanness; a person who touches any such shall be unclean until evening, and shall not eat of the holy gifts unless he has bathed his body in water. But when the sun sets, he will be clean, and afterward he shall eat of the holy gifts, for it is his food." (Leviticus 22:4-7)
"Aaron and his sons shall wash their hands and their feet from it [bronze laver]; when they enter the tent of meeting, they shall wash with water, so that they will not die; or when they approach the altar to minister, by offering up in smoke a fire sacrifice to the LORD." (Exodus 30:19) The priests, the sons of Aaron must wash their hands and feet before ministering in the tabernacle or Temple.