Leviticus 21:3-5

Complete Jewish Bible

³ he may also make himself unclean for his virgin sister who has never married and is therefore dependent on him. ⁴ He may not make himself unclean, because he is a leader among his people; doing so would profane him. ⁵ Cohanim are not to make bald spots on their heads, mar the edges of their beards or cut gashes in their flesh.