QUESTIONS: The Gemara discusses whether a Kohen Gadol who is also a Nazir may become Tamei in order to bury a Mes Mitzvah. TOSFOS (DH l'Aviv) and the Gemara in Zevachim (100a) discuss whether a Kohen Hedyot who is also a Nazir may become Tamei for a Mes Mitzvah.

(a) What is the Gemara's question? The principle of "Ein Isur Chal Al Isur" teaches that a second Isur cannot take effect on a pre-existing Isur. Hence, Isur of Tum'ah of Nezirus should not be able to take effect on the pre-existing Isur of Tum'ah of Kehunah. (SHA'AGAS ARYEH #60)

(b) The Gemara in Ta'anis (17a) teaches that a Kohen Gadol is obligated to cut his hair once a week. A Nazir, however, is prohibited from shaving his hair for at least thirty days. How is it possible for a Kohen Gadol to become a Nazir? The Nezirus should not take effect since it contradicts the obligations of the Kohen Gadol.

(a) The SHA'AGAS ARYEH answers that the Isur of Tum'ah of Nezirus takes effect on a Kohen through the mechanism of "Isur Kolel": when the second Isur includes more objects than the first Isur, the second Isur take effect on all of the objects, even those prohibited by the first Isur. When the Isur of Nezirus takes effect, it includes more than just the Isur of Tum'ah; it includes an Isur to shave and an Isur to eat grape products. Since it takes effect with regard to those other items, it also takes effect with regard to Tum'ah.

However, the AVNEI MILU'IM (#15) asks that two different types of Isur normally cannot constitute an "Isur Kolel." That is, an Isur must prohibit two of the same type of item in order to be considered an "Isur Kolel," such as an Isur which prohibits two items of food or two forms of Tum'ah. An Isur which prohibits food and also prohibits Tum'ah (like the Isur of Nezirus) is not considered an "Isur Kolel."

The Avnei Milu'im therefore suggests that the "Isur Kolel" of a Kohen Hedyot who becomes a Nazir is that the Isur of Nezirus prohibits him from becoming Tamei even for close relatives (for whom he was permitted to become Tamei as a Kohen Hedyot). Since the Isur of Nezirus prohibits him from becoming Tamei from those relatives, one might have thought that it also prohibits him through "Isur Kolel" from becoming Tamei for a Mes Mitzvah.

However, this approach does not explain why the Isur Tum'ah of Nezirus should take effect on a Kohen Gadol. A Kohen Gadol may not become Tamei for close relatives even without the Isur of Nezirus! The HAGAHAH on the Avnei Milu'im writes that perhaps the Gemara's case of a Kohen Gadol who becomes a Nazir refers to a Kohen who is not yet a Kohen Gadol, who accepts upon himself to become a Nazir at the exact moment at which he is appointed Kohen Gadol. In such a case, the Isur Tum'ah of Nezirus is able to take effect simultaneously with the Isur Tum'ah of a Kohen Gadol. They take effect "b'Vas Achas," and thus it is not a case of "Isur Chal Al Isur."

The KEREN ORAH suggests another reason for why the Isur Tum'ah of Nezirus takes effect on the Isur Tum'ah of Kehunah. He refers to the Gemara earlier (4a) which cites a verse that teaches that Nezirus is an exception to the rule of "Ein Isur Chal Al Isur." The Gemara there says that the Isur which prohibits a Nazir from drinking wine is able to take effect on a pre-existing Isur (such as when the person had made a Shevu'ah not to drink wine, according to Tosfos' understanding of Rebbi Shimon; see Insights there). Similarly, the Isur Tum'ah of a Nazir can take effect on the pre-existing Isur Tum'ah of Kehunah.

(b) The Mitzvah of a Kohen Gadol to shave each week is only a Mitzvah d'Rabanan. It is neither a Mitzvah d'Oraisa nor a Halachah l'Moshe mi'Sinai. Therefore, the Isur d'Oraisa which prohibits a Nazir from shaving overrides the Mitzvah d'Rabanan that a Kohen Gadol shave each week.

Alternatively, according to the KEREN ORAH cited above -- who maintains that it is possible to derive the laws of the Isur of Tum'as Mes of a Nazir from the laws of the Isur to drink wine -- the following answer may be suggested. Just as the Isur of Nezirus overrides a Mitzvah to drink wine (such as when the person had made a Shevu'ah to drink wine), so, too, the Isur of Nezirus overrides the Mitzvah of a Kohen Gadol to shave his hair once a week.

However, this answer is not valid here because the verse teaches that an act of Gilu'ach of a Mitzvah (such as the Mitzvah of a Metzora to shave) does override the Isur of a Nazir to shave in the case of a Nazir who becomes a Metzora. This is derived from the word "Rosho" in the verse which discusses the Metzora's Mitzvah to shave (Vayikra 14:9). The Gemara earlier (44a) discusses the difference between a Mitzvah to perform Gilu'ach, which does override the Isur of a Nazir to shave, and a Mitzvah to drink wine, which does not override the Isur of a Nazir to drink wine.

Accordingly, if the Mitzvah for a Kohen Gadol to shave his hair each week is mid'Oraisa, indeed a Nazir who is a Kohen Gadol must shave his hair each week (since the Mitzvah of the Kohen Gadol to shave overrides the Isur of a Nazir to shave). At the end of his Nezirus he will have to step down from the position of Kohen Gadol in order to grow his hair for thirty days so that he can perform the Gilu'ach of a Nazir and offer his Korbenos Nezirus.