Leviticus 22:3-7

Give them the following instructions. “In all future generations, if any of your descendants is ceremonially unclean when he approaches the sacred offerings that the people of Israel consecrate to the LORD, he must be cut off from my presence. I am the LORD. “If any of Aaron’s descendants has a skin disease or any kind of discharge that makes him ceremonially unclean, he may not eat from the sacred offerings until he has been pronounced clean. He also becomes unclean by touching a corpse, or by having an emission of semen, or by touching a small animal that is unclean, or by touching someone who is ceremonially unclean for any reason. The man who is defiled in any of these ways will remain unclean until evening. He may not eat from the sacred offerings until he has bathed himself in water. When the sun goes down, he will be ceremonially clean again and may eat from the sacred offerings, for this is his food.