Nazir 61A

תני רבי חייא: זה לפני ביאת מים (חיים) וזה לאחר ביאת מים, זה לפני זריקת דמים וזה לאחר זריקת דמים.

R' Ḥiyya teaches the same halakha: The shaving of a metzora does not count for the shaving of naziriteship, as this one, a metzora, shaves before immersion in water, and that one, an impure nazirite, shaves after immersion water. This one, the metzora, shaves before the blood is sprinkled, and that one, the pure nazirite, shaves after the blood is sprinkled.

שתגלחת הנגע וכו׳. בעי רמי בר חמא: הני ארבע תגלחיות דקאמר, משום מצוה, או משום אעבורי שער טומאה?

§ The Mishnah taught that the shaving of tzara'at overrides the shaving of a nazirite only when he is a confirmed metzora. Rami bar Ḥama raises a dilemma: Those 4 shavings about which the tanna spoke, the 4 that a nazirite performs for his tzara'at and impurity, are they all due to the mitzva of shaving, or are some of them not performed for the sake of a mitzva, but for the sake of removing hair that grew in impurity, so that other hair can grow?

למאי נפקא מינה? לעבורי בנשא. אי אמרת משום מצוה ⁠— לעבורי בנשא לא, ואי אמרת משום אעבורי שער טומאה ⁠— אפילו סכיה נשא נמי.

The Talmud asks: What is the difference whether he shaves for one reason or another? The Talmud explains: It is relevant with regard to removing hair with a depilatory. If you say that the reason is due to a mitzva, removing with a depilatory is not an option, as the mitzva is specifically to shave. But if you say the reason is due to the removal of hair of impurity, even if he rubs it with a depilatory that is also effective.

מאי? אמר רבא, תא שמע: ומגלח ארבע תגלחיות. אי סלקא דעתך משום עבורי שער טומאה, אפילו בשלש נמי סגיא ליה! שמע מינה משום מצוה: שמע מינה.

What then is the halakha? Rava said: Come and hear a resolution from a baraita (Tosefta 6:1): And he shaves with 4 acts of shaving. Now if it should enter your mind that the reason is for the sake of removing hair of impurity, even 3 shavings should be enough for him, two for his tzara'at, and the last one for his naziriteship of purity. Since the third shaving is performed only to remove his hair of impurity so that he can start his pure naziriteship afresh, why is it included? Conclude from the baraita that all 4 shavings are due to the mitzva of shaving. The Talmud says: Conclude from the baraita that this is the case.