Leviticus 21:1-5

1The Lord said to Moses, “Speak to Aaron’s sons, the priests, and tell them: A priest is not to make himself ceremonially unclean for a dead person among his relatives,

2except for his immediate family: his mother, father, son, daughter, or brother.

3He may make himself unclean for his unmarried virgin sister in his immediate family.

4He is not to make himself unclean for those related to him by marriage and so defile himself.

5“Priests may not make bald spots on their heads, shave the edge of their beards, or make gashes on their bodies.