Numbers 6:8

5 All the time he is under his oath let no blade come near his head; till the days while he is separate are ended he is holy and his hair may not be cut.

6 All the time he is separate he may not come near any dead body.

7 He may not make himself unclean for his father or his mother, his sister or his brother, if death comes to them; because he is under an oath to keep himself separate for God.

8 All the time he is separate he is holy to the Lord.

9 If death comes suddenly to a man at his side, so that he becomes unclean, let his hair be cut off on the day when he is made clean, on the seventh day.

10 And on the eighth day let him take to the priest, at the door of the Tent of meeting, two doves or two young pigeons;

11 And the priest will give one for a sin-offering and the other for a burned offering to take away the sin which came on him on account of the dead, and he will make his head holy that same day.