Leviticus 21:10

The priest who is highest among his brothers, who has had the anointing oil poured on his head and has been ordained to wear the priestly garments, must not let his hair hang loose or tear his garments.

Note Or must not uncover his head

And he that is the high priest among his brethren, upon whose head the anointing oil was poured, and that is consecrated to put on the garments, shall not uncover his head, nor rend his clothes;

“‘He who is the high priest among his brothers, upon whose head the anointing oil is poured, and who is consecrated to put on the garments, shall not let the hair of his head hang loose, or tear his clothes.

And he that is the high priest among his brethren, upon whose head the anointing oil is poured, and that is consecrated to put on the garments, shall not let the hair of his head go loose, nor rend his clothes;