Leviticus 21:10-11

¹⁰The high priest has the highest place among the other priests. He has been anointed with olive oil poured on his head and has been ordained to wear the priestly clothing. He must not leave his hair uncombed or tear his clothes.

¹¹He is not to go near any dead body. He must not make himself unclean, even it is for his own father or mother.