Leviticus 21:3

New King James Version

also his virgin sister who is near to him, who has had no husband, for her he may defile himself.

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except for his relatives who are nearest to him: his mother, his father, his son, his daughter, and his brother;

Otherwise he shall not defile himself, being a chief man among his people, to profane himself.

If the priest’s daughter is married to an outsider, she may not eat of the holy offerings.