Leviticus 21:1-4

1And the LORD said unto Moses, Speak unto the priests the sons of Aaron, and say unto them, There shall none defile himself for the dead among his people;

2except for his kin, that is near unto him, for his mother, and for his father, and for his son, and for his daughter, and for his brother;

3and for his sister a virgin, that is near unto him, which hath had no husband, for her may he defile himself.

4He shall not defile himself, being a chief man among his people, to profane himself.