Ezra 2:62
These sought their listing among those that were reckoned by genealogy, but they were not found: therefore were they, as defiled, excluded from the priesthood.
Numbers 3:10
And you shall appoint Aaron and his sons, and they shall wait on their priest's office: and the stranger that comes near shall be put to death.
Leviticus 21:21-23
No man that has a blemish of the descendants of Aaron the priest shall come near to offer the offerings of the LORD made by fire: he has a blemish; he shall not come near to offer the bread of his God.
Numbers 16:39-40
And Eleazar the priest took the bronze censers, with which they that were burned had offered; and they were hammered out for a covering of the altar:
Numbers 18:7
Therefore you and your sons with you shall keep your priest's office for everything at the altar, and within the veil; and you shall serve: I have given your priest's office unto you as a gift for service: and the stranger that comes near shall be put to death.
Ezekiel 44:10-14
And the Levites who have gone away far from me, when Israel went astray, who went astray away from me after their idols; they shall even bear their iniquity.