What does "Kadosh Yih'yeh" mean? What is it referring to?
Rashi (like Shmuel, Ta'anis 11a): It means that the hair of his head 1 is holy, and he must therefore allow it to grow.
Seforno (like R. Elazar, Ta'anis 11a): It means that the Nazir is holy, inasmuch as he abstains from his materialistic desires.
See Sifsei Chachamim.
What is the meaning of "Pera Se'ar Rosho"?