Nazir 18A

דאי סלקא דעתך תגלחת טומאה, ימי חלוטו מי לא בעי תגלחת? לא, תגלחת דנזירות קתני.

as if it enters your mind to say that the baraita is discussing the shaving done as a result of the nazirite’s impurity, and contrasts a nazirite with a metzora, do the end of a metzora’s days of confirmed tzara'at not require shaving? A metzora must shave when he is purified from his condition, so how can he be described as unfit for shaving? Rather, the baraita must be referring to the nazirite’s shaving of purity, as suggested above (17b). The Talmud rejects this: No, it could be that the baraita is discussing the shaving done as a result of the nazirite’s impurity, and when it states that a metzora is unfit for shaving, the baraita is teaching about the shaving of naziriteship, and the baraita is stating that a metzora is unfit for any shaving of a nazirite, since he must first shave for his tzara'at.

תא שמע: ״וטמא ראש נזרו״, בטהור שנטמא הכתוב מדבר, שהוא טעון העברת שער והבאת ציפרין. ולפטור את הנזיר בקבר ⁠— שאין טעון העברת שער והבאת ציפרין.

The Talmud suggests another proof to answer the question of whether one who vows naziriteship while in a cemetery must shave upon undergoing purification. Come and hear a baraita: The verse states: “And he defiles his consecrated head, he should shave his head on the day of his purification, on the 7th day should he shave it” (Numbers 6:9). The baraita explains: The verse is speaking of a ritually pure nazirite who became impure, who requires hair removal and the bringing of birds as offerings. And this verse comes to exempt a nazirite who vowed while in the grave, i.e., a cemetery, that he does not require hair removal and the bringing of birds.