Leviticus 22:9-11

Amplified Bible

⁹ Therefore the priests shall observe My ordinance, so that they will not bear sin because of it and die if they profane it; I am the Lord who sanctifies them.

¹⁰ ‘No layman [that is, someone outside of Aaron’s family] is to eat the holy gift [which has been offered to God]; a foreigner residing with the priest or a hired man shall not eat the holy thing. ¹¹ But if a priest buys a slave as his property with his money, the slave may eat the holy thing, and those who are born in the priest’s house; they may eat his food.