“All the days of his naziriteship he is holy to the Lord” (Numbers 6:8). “All the days of his naziriteship he is holy to the Lord.” Why is it stated? Because it says: “until completion of the days” (Numbers 6:5) – I only have those for whom there is an end to their naziriteship, from where do I derive [the concept that there may be] an eternal nazirite? The verse states: “All the days of his naziriteship,” to include an eternal nazirite. “He is holy to the Lord,” this is the sanctity of the body.116That he may not make it impure through coming in contact with a corpse.
Midrash on Numbers
Bamidbar Rabbah 10:12