Leviticus 21:4-6 New International Version - UK (NIVUK)
4 He must not make himself unclean for people related to him by marriage,[a] and so defile himself.
5 ‘“Priests must not shave their heads or shave off the edges of their beards or cut their bodies. 6 They must be holy to their God and must not profane the name of their God. Because they present the food offerings to the Lord, the food of their God, they are to be holy.