Leviticus 22:1-7

1 The LORD spoke to Moses,
2 "Tell Aaron and his sons that they must respect the holy offerings which the Israelites set apart for me. In this way they will not dishonor my holy name. I am the LORD.
3 "Tell them: In future generations if any of your descendants, while unclean, comes near the holy offerings the Israelites set apart for the LORD, that person must be excluded from my presence. I am the LORD.
4 "No descendant of Aaron who has a skin disease or a discharge may eat any of the holy offerings until he is clean. Any person who has an emission of semen or touches a dead body,
5 an unclean swarming creature, or an unclean person
6 will be unclean until evening. He must not eat any of the holy offerings unless he has washed himself.
7 When the sun has set, he will be clean. Then he may eat the holy offerings because they are his food.