Leviticus 22:3-7

3“Say to them: ‘For the generations to come, if any of your descendants is ceremonially unclean and yet comes near the sacred offerings that the Israelites consecrate to the Lord, that person must be cut off from my presence. I am the Lord. 4“ ‘If a descendant of Aaron has a defiling skin disease or a bodily discharge, he may not eat the sacred offerings until he is cleansed. He will also be unclean if he touches something defiled by a corpse or by anyone who has an emission of semen, 5or if he touches any crawling thing that makes him unclean, or any person who makes him unclean, whatever the uncleanness may be. 6The one who touches any such thing will be unclean till evening. He must not eat any of the sacred offerings unless he has bathed himself with water. 7When the sun goes down, he will be clean, and after that he may eat the sacred offerings, for they are his food.