Leviticus 22:4-7

4No man of the descendants of Aaron who is a leper or has a discharge may eat the holy things [the offerings and the showbread] until he is clean. And whoever touches any person or thing made unclean by contact with a corpse or a man who has had a seminal emission,

5or whoever touches any crawling thing by which he is made unclean, or any person by whom he is made unclean, whatever it may be,

6the person who touches any such thing shall be unclean until evening and shall not eat the holy things unless he has bathed his body in water.

7When the sun sets, he will be clean, and afterward he may eat the holy things, for it is his food.