Numbers 6:6-7

6:6 “‘All the days that he separates himself to the Lord he must not contact a dead body. 6:7 He must not defile himself even for his father or his mother or his brother or his sister if they die, because the separation for his God is on his head.

Numbers 6:11

6:11 Then the priest will offer one for a purification offering and the other as a burnt offering, and make atonement for him, because of his transgression in regard to the corpse. So he must reconsecrate his head on that day.