Shaving: Forbidden to Nazarites

For the entire period of his vow of separation, no razor shall touch his head. He must be holy until the time of his separation to the LORD is complete; he must let the hair of his head grow long.

For behold, you will conceive and give birth to a son. And no razor shall touch his head, because the boy will be a Nazirite to God from the womb, and he will begin the deliverance of Israel from the hand of the Philistines.”