Leviticus 21:10-12

10“ ‘The high priest, the one among his brothers who has had the anointing oil poured on his head and who has been ordained to wear the priestly garments, must not let his hair become unkempt or tear his clothes. 11He must not enter a place where there is a dead body. He must not make himself unclean, even for his father or mother, 12nor leave the sanctuary of his God or desecrate it, because he has been dedicated by the anointing oil of his God. I am the Lord.