Numbers 6:7-9

Amplified Bible

⁷ He shall not make himself [ceremonially] unclean for his father, mother, brother, or sister, when they die, because [the responsibility for] his separation to God is on his head. ⁸ All the time of his separation he is holy to the Lord.

⁹ ‘If a man dies very suddenly beside him, and he defiles his dedicated head, then he shall shave his head on the day that he becomes [ceremonially] clean; he shall shave it on the seventh day [the end of the purification period].