Besides the religious nature of this institution, it seems to have been partly of a civil and prudential use.
The sobriety and temperance which the Nazarites were obliged to observe were very conducive to health.
Accordingly, they were celebrated for their fair and ruddy complexion; being said to be both whiter than milk and more ruddy than rubies (La 4:7); the sure signs of a sound and healthy constitution.
It may here be observed, that when God intended to raise up Samson, by his strength of body, to scourge the enemies of Israel, he ordered, that from his infancy he should drink no wine, but live by the rule of the Nazarites, because that would greatly contribute to make him strong and healthy; intending, after nature had done her utmost to form this extraordinary instrument of his providence, to supply her defect by his own supernatural power.
See Jenning's Jewish Antiquities, B. I. c. 8.