Numbers 6:4

All the days of his separation— It is not said how many days, for there was no stated number; every one devoted himself for as long time as he chose. But not for a less time, says Houbigant, than might be sufficient for the hair to grow, which, at the completion of the time, the Nazarite was to burn in the fire of the altar, (see Numbers 5:18.) whereby those Jews are refuted who assign the number of thirty days to Nazariteship. They should have assigned a year at least; for the hair can scarcely grow in a less interval from a shorn head. Some, however, were perpetual Nazarites, being peculiarly devoted to God from the womb; as Samson, and John the Baptist. It is considered as a happiness, and mark of God's favour to the Jewish nation, to have such persons raised up among them to be examples of a holy life. I raised up of your sons for prophets, and of your young men for Nazarites. Amos 2:11. It appears from 1 Maccab. Numbers 3:49 that they were accustomed to make such vows, more especially in times of calamity; and in how high esteem they were on account of their sanctity, we learn from Lamentations 4:7. Her Nazarites were purer than snow.