It is not actually a Halachic requirement that the Kohen Gadol gets a haircut every Erev Shabbos. It is beautiful and stylisitic if he can do this, but the Halachic obligation is fulfilled if the Kohen Gadol takes a haircut every 30 days.

[see Teshuvot Shoel uMeshiv 4th edition part 2 chapter 162]

Best wishes

Dovid Bloom

1) The Sho'el u'Meshiv, that I cited above, writes that it appears from the Rambam (Hilchos Klei ha'Mikdash 5:6) that the reason why a Kohen Gadol is not allowed to grow long hair is because of his honor and glory. The Rambam there (5:7) also writes, "His glory and honor is to remain in the Mikdash the entire day." The Sho'el u'Meshiv writes that this is a glory both for the Beis ha'Mikdash and for the Kohen Gadol.

2) Now, the glory of the Nazir is somewhat the opposite. His holiness and honor is that he grows his hair, as the Torah says, "For the crown of Hash-m is on his head" (Bamidbar 6:7). The Sho'el u'Meshiv asserts that if a Kohen Gadol decides to become a Nazir, this is even an additional glory for him, since he has now volunteered to separate himself from all physical desires.

3) It follows that when the Rambam (5:6) writes that the Kohen Gadol takes a haircut every Erev Shabbos, this refers to a regular Kohen Gadol, but for the specially holy Kohen Gadol who is also a Nazir, the greatest glory is to take a haircut like a Nazir, namely every 30 days.

4) The Mishnah in Nazir 4a states that if the hair of a Nazir Olam grew long and became heavy he may lighten it with a razor. One week is not sufficient for the hair to become heavy.

An apology and a source for the Shoel u'Meshiv from Rabeinu Bachye:

1) First, I must apologize for reading the Shoel u'Meshiv incorrectly. The Shoel u'Meshiv in fact writes that one cannot say that it is only admirable for the Kohen Gadol to take a haircut every Friday, but it is not a chiyuv, because the Rambam (Hilchos Klei ha'Mikdash 5:6) cites the obligation for a haircut every week under the prohibition of "he shall not allow his hair to grow" (Vayikra 21:10). So your question on me, Josh, was exactly what the Shoel u'Meshiv asks on his own original possible explanation and rejects it because of this question. As a result of this question, the Shoel u'Meshiv proceeds to give the answer that I cited in my second reply, that the glory of the Nazir not cutting his hair is greater than the glory of the Kohen Gadol cutting his hair, so the Kohen Gadol who is a Nazir waits 30 days. The correct Peshat in the Sho'el u'Meshiv is the one I cited in my second reply, not the one in my first reply.

2) I think that I found, bs'd, a source for the Sho'el u'Meshiv in Rabeinu Bachye (Bamidbar 3:6, DH v'A'D). He writes that the Nazir is "higher" than the Kohen Gadol. In fact, Rabeinu Bachye there is following the Kabalah, but I also found in the Sefer Ta'amei ha'Mitzvos (by Rav Mencahem ha'Bavli, who lived in the time of the Beis Yosef in Tzefat) in Mitzvah 221 that we learn from the verse, "when a man does a wonder" (Bamidbar 6:2), that a Nazir is a "Peleh." The Kohen is holy because he is from the seed of Aharon, which is an advantage that the Nazir does not possess. Nevertheless, the Torah says about a Nazir that "the crown of Hash-m is on his head" (Bamidbar 6:7). This means that the holiness of the Nazir, who is a Yisrael, is higher than that of the Kohen because he did a "wondrous thing" when he agreed to subjugate his Yetzer ha'Ra in favor of his Yetzer ha'Tov and separated himself from worldly plaesures. The Nazir is greater than the Kohen because he reached his high level through his own free will.

3) So now we can answer the original question. A Kohen Gadol can be a Nazir because he is adding on extra Kedushah to himself. The fact that he misses the haircut every week is overriden by the fact that he acquires the Crown of the Nazir after 30 days.

4) I found, bs'd, that the Me'iri asks this question in Berachos 20a (DH Meis Mitzvah). He gives two answers:

(a) "Shema Yom Lamed Oleh l'Kan ul'Kan" -- "perhaps day 30 counts both for this and for this."

We can explain this by saying that for the Nazir, "Miktzas ha'Yom k'Kulo" -- a Nazir is allowed to cut his hair on day 30 since it is sufficient that he avoids cutting his hair for part of day 30. In contrast, a Kohen Gadol transgresses the prohibition of growing his hair too long only if he waits a full 30 days. (See Sefer Parshas ha'Shavu'a, by Rav Yeshayah Shechter of Bnei Brak, Parshas Shemini, p. 53, DH ub'Zeh.)

However, we do see from the Me'iri that a Kohen Gadol does not transgress the prohbition of long hair at less than 30 days. Possibly, this is consistent with the original idea of the Sho'el u'Meshiv that I cited in my first reply, that cutting the hair every Friday is only a good thing to do, but not a Chiyuv, or possibly the Me'iri agrees with another of the Rishonim, the Sefer Yere'im (#291) who says that the extra prohibition of the Kohen Gadol growing hair is only mid'Rabanan. Therefore, when the Kohen Gadol is also a Nazir, we may argue that the d'Rabanan prohbition of more than seven days is overriden by the d'Oraisa prohibition of the Nazir cutting his hair before 30 days.

(b) The Me'iri also writes that possibly the scenario here is of a regular Kohen who has started to be a Nazir and is then appointed as Kohen Gadol. He has less than seven days to go until the end of his Nezirus, so he is able to take a haircut on the Friday.

5) Here is the answer of the Minchas Chinuch: The Minchas Chinuch (149:7) writes that if a Kohen Gadol accepted upon himself to be a Nazir he is certainly not allowed to cut his hair. He writes that it may be that we say in this case, "Aseh Docheh Lo Ta'aseh," the positive Mitzvah that the Nazir has of "he shall be holy and grow his hair" (Bamidbar 6:5) overrides the negative Mitzvah of the Kohen Gadol of "he must not grow his hair" (Vayikra 21:10). However, even if we do not say "Aseh Docheh Lo Ta'aseh," he still may not take a haircut because he will thereby transgress the prohibition of the Nazir of "a razor may not come upon his head" (Bamidbar 6:5), so the prohibition of the Kohen Gadol not to grow his hair does not override the prohibition of the Nazir. The Lav of the Kohen Gadol is passive while the lav of the Nazir is active, so it is better to transgress the passive prohibition.

We see from the Minchas Chinuch that if a Kohen Gadol does become a Nazir, then he must passively let his hair grow, rather than actively cut it and transgress his Nezirus. However, the question can still be aked on the Minchas Chinuch: How is the Kohen Gadol allowed to get himself into this situation in the first place, to become a Nazir when he knows this is going to mean that he will transgress the Halachah of Kohen Gadol and grow his hair? (See Beis Yitzchak, cited in note 7 to the Machon Yerushalayim edition of the Minchas Chinuch.)

6) There is a Sefer called Teshuvos Rachash Leivav (by the son-in-law of Rebbi Akiva Eiger) (#16, p. 57, DH v'Al Ikar) who answers this question with a similar idea to that of the Sho'el u'Meshiv that I cited in my second reply. He writes that being a Nazir is not a small matter even for a Kohen Gadol. The Kohen Gadol should also sanctify himself and become a Nazir of Hash-m. How is it possible to say that the entire Parshah of Nezirus is not addressed to the Kohen Gadol at all? When the Torah says that a Kohen Gadol may not grow his hair, this applies only where he does so for an optional reason, but if he does this in order to fulfill the great Mitzvah of Nezirus, he may grow his hair.

Dovid Bloom

1) a) I want to suggest that Rashi (Megilah 9b, DH Kol Mitzvos), when he writes, "Lo Pore'a v'Lo Porem," is chiefly referring to Aveilus. The reason I say this is because the Gemara in Yoma 73a records a Beraisa that tells us the differences between a Kohen Gadol and a Kohen Hedyot. One of the differences is "Lo Pore'a v'Lo Porem" (then the Beraisa states that there are certain ways that Porem can be done.) I argue that Rashi took the words "Lo Pore'a v'Lo Porem" from Yoma 73a. Now, Rashi in Yoma 73a (DH Lo Pore'a) writes that this means the Kohen Gadol must not grow his hair out of mourning. This suggests that a Kohen Hedyot may grow his hair out of Aveilus.

b) This is in fact stated by the Ritva to Moed Katan 14b. The Gemara there (four lines from the bottom) states, "veha'Tzaru'a - to include a Kohen Gadol." Rashi writes that this means that a Kohen Gadol can also be a Metzora. The Ritva there writes that a Kohen Gadol does not do Periyah and Perimahon the deceased, while it is obvious that a Kohen Hedyot does do Periyah and Perimah for mourning.

c) So this is what Rashi in Megilah 9b means: the Kohen Gadol does not do Periyah and Perimah when he is an Ovel, but a Kohen Hedyot does. According to this there is no proof from Rashi that a Kohen Gadol has an Isur to let his hair grow for less than 30 days.

Reb Moishy, thank you so much for showing interest in what I write! Yasher Ko'ach Gadol!

2) Regarding the Peshat in Rashi, I spoke to a Talmid Chacham about this question and he said that Rashi (9b) merely cites the Dinim from the verses. The verse in Vayikra 21:10 says "Lo Yifra v'Lo Yifrom," so Rashi writes "Lo Pore'a v'Lo Porem." It is true that Yechezkel 44:20 states, "They may not let their hair grow long," which applies to all Kohanim and not only to the Kohen Gadol, but this is a verse in Navi and not in the Chumash, so Rashi does not mention it. Rashi mentions the aspects mentioned specifically in the Chumash for which a Kohen Gadol must be more stringent than a Kohen Hedyot (see Zevachim 16a that the Din that the Kohen Gadol may bring a Korban when he is an Onen is effectively mentioned specifically in the Chumash).

3) a) In my second reply, I apologised for not citing the Sho'el u'Meshiv accurately when I wrote that it is only a nice practice for a Kohen Gadol to cut his hair every Friday but not a Chiyuv. At the beginning of the Teshuvah, the Sho'el u'Meshiv writes that one cannot say this explanation. However, I have now seen that at the end of the Teshuvah he comes back to what he rejected earlier on because he cites the Rambam (Hilchos Bi'as ha'Mikdash 1:11) who writes, "How long may they (either the Kohen Gadol or Kohen Hedyot) wait without cutting their hair?" The Rambam answers that it is 30 days, just like a Nazir. The Rambam concludes that, therefore, a Kohen Hedyot who is serving in the Beis ha'Mikdash takes a haircut once every 30 days.

b) We learn from the Rambam that (a) the prohibition of growing the hair is only transgressed after 30 days. This is seen from the fact that in 1:10, the Rambam discusses the prohibition of growing hair both for the Kohen Hedyot and the Kohen Gadol and writes that it is 30 days. (b) A Kohen Hedyot cuts his hair every 30 days. This implies that a Kohen Gadol cuts his hair more often, and this is completed by what the Rambam writes (Hilchos Klei ha'Mikdash 5:6), that the Kohen Gadol cuts his hair every Friday.

c) The Sho'el u'Meshiv therefore comes to the conclusion that the Kohen Gadol cutting his hair every Friday is a stylish thing to do, but not obligatory. We now have an answer to our original question: a Kohen Gadol can be a Nazir and he will cut his hair every 30 days, as a Nazir or Kohen Hedyot do l'Chatchilah. In this case, the Kohen Gadol will wait 30 days for the haircut, just like a Kohen Hedyot, and he transgresses no prohibition in doing so.

d) Now, just to fill in what I wrote in the third answer about the Me'iri (Berachos 20a, end of DH Meis Mitzvah): The Me'iri asks, "How can one ever find a Kohen Gadol who is also a Nazir? Is the Kohen Gadol not forbidden to grow his hair?!" If we pay close attention, we notice that the Me'iri does not ask from the fact that the Kohen Gadol cuts his hair every Friday. We can say that this is because it was obvious to the Me'iri that the Friday haircut is only for additional beauty, but not an obligation (the same point that the Sho'el u'Meshiv reached in his conclusion). Rather, the question of the Me'iri was slightly different. He was worried by the fact that the Nazir may not cut his hair until day 30, while the Kohen Gadol is obligated to cut his hair by day 30, so we are faced with a conflict. The Me'iri answers, "Possibly 'Yom Lamed Oleh l'Kan ul'Kan.'" These words are in fact found in the Gemara in Nazir 6a. Here, what the Me'iri means is that since "Miktzas ha'Yom k'Kulo" as Nazir 6a states, this means that the Nazir may take his haircut in the middle of day 30, since if he refrained from a haircut until the middle of day 30 he has thereby fulfilled his obligation as a Nazir. But he still has remaining time before he transgresses the prohibition of a Kohen Gadol waiting too long for a haircut, because Rashi (Sanhedrin 83a, DH u'Feru'ei Rosh) writes that the prohibition is if the Kohen did Avodah when more than 30 days had gone by without taking a haircut. He transgresses only if he gets to day 31 without a haircut. Therefore, the Kohen Gadol who is also a Nazir takes a haircut in the middle of day 30. This is long enough for a Nazir to wait, and not too long for a Kohen Gadol to wait.

Dovid Bloom