Abaye and Rava ask two specific questions about the Gilu'ach of a Nazir. Both questions, however, seem difficult to understand.

(a) Abaye asks that if a Nazir shaves off all but two of his hairs and leaves those two hairs while the rest of his hair grows back, and then at the end of his Nezirus he cuts those two hairs, has he performed a valid Gilu'ach or must he cut the rest of his hair again as well?

What is the basis for Abaye's question? What reasons are there to say that cutting the two hairs is, or is not, a valid Gilu'ach?

(b) Rava asks what the Halachah would be in a case in which a Nazir shaves off all of his hair except for two hairs, and then one of those two hairs falls out, and he shaves the remaining hair. The Gemara concludes that this would not be a valid form of Gilu'ach, and thus the Nazir must wait until the hair grows back and then perform another Gilu'ach.

What is Rava's basis to assume that such a Gilu'ach would be valid? If the Nazir leaves two hairs, such a Gilu'ach obviously is not valid; the Halachah states that two hairs are "Me'akev" the Gilu'ach of a Nazir. If the Nazir left two hairs and one of them subsequently fell out by itself, the Nazir never performed a proper Gilu'ach.

Moreover, why does Rava specifically ask about a Nazir who "cut off" the last hair? What difference does it make whether the Nazir cut off the last hair or it fell out?

Finally, why does Rava ask only about a case in which only two hairs were left and the first of those two hairs fell out? The same question should apply in a case in which three hairs were left, the first hair fell out, and the Nazir cut the remaining two.

(a) The Rishonim (see SHITAH MEKUBETZES) explain that Abaye's question is whether the Mitzvah of Gilu'ach of a Nazir requires that the Nazir cut off all his hair, or that he make his head bald. If the Mitzvah requires that he cut off his hair, he fulfills the Mitzvah in this case, even though some of the hair grows back before he cuts off the rest of it. Since, in the end, he cuts off all of the hair that was on his head at the time he began his act of Gilu'ach, he fulfills the Mitzvah. The new hair that grows does not have to be cut as part of the Mitzvah of Gilu'ach, because those hairs were already cut, and thus the Nazir has fulfilled his obligation to cut off his hair. On the other hand, if the Mitzvah of Gilu'ach is to make the head bald, when new hair grows in the Mitzvah will not be complete until he cuts not only the remaining hairs but also the new hairs that grew. He must make the head bald in order to fulfill the Mitzvah of Gilu'ach.

The Rishonim seem to disagree about whether Abaye means that even a growth of hair that is less than "Kedei la'Chof Rosho l'Ikro" prevents the Gilu'ach from being valid (and therefore the Nazir must wait for that hair to grow the amount of "Kedei la'Chof" and then cut it), or whether he means that such a small growth is ignored and Abaye's question applies only if the hair grows "Kedei la'Chof." (The subject of dispute might be whether the requirement to have "Gilu'ach k'Ein Ta'ar" excludes any hair smaller than "Kedei la'Chof" or even extremely short hair.)

(b) The SHITAH MEKUBETZES and RABEINU PERETZ explain that Rava's question is whether or not the hair that falls out interrupts the Gilu'ach with an irrevocable "Hefsek." If the hair that falls out is not the second to the last hair, but there are still many hairs left on the head at the time it falls out, it is clear that the loss of that strand of hair is not an interruption, a "Hefsek," in the Gilu'ach. Since the remaining hair still contains a Shi'ur Gilu'ach (i.e. more than two hairs), he may continue the Gilu'ach. Conversely, if only two hairs remain and both fall out, it is obvious that the Gilu'ach is not valid since the Nazir did not complete the Gilu'ach (since hair in the amount of the Shi'ur of Gilu'ach -- two hairs -- fell out by itself).

The question of Rava arises when two hairs remain and only the first one of those hairs falls out. When the Nazir cuts the last hair, is his act considered a continuation of the Gilu'ach and it makes no difference whether the hair fell out when many hairs remained or when only one hair remained? Perhaps since the minimum number of hairs that comprise a Gilu'ach is two, and after one hair fell out only one hair remained, the cutting of the last hair by itself cannot constitute a Gilu'ach, and so, too, it cannot be part of the Gilu'ach the Nazir performed already (when he left two hairs). The Gemara concludes that it is not considered a Gilu'ach, because the hair that fell out separates the last hair from the act of Gilu'ach.

QUESTION: The Mishnah teaches that a Nazir may wash his hair with shampoo ("Chofef") and may untangle or part his hair ("Mesfaspes"), but he may not comb his hair. The Gemara explains that a Nazir is prohibited from combing his hair because one who combs his hair "has intention to remove the loose hairs," and thus the Nazir will intentionally transgress the prohibition against removing hair.

The Gemara implies that the removal of hair through combing is not considered a "Davar she'Eino Miskaven" but rather a "Davar Miskaven"; the Nazir has intention to remove his hair when he combs it.

RASHI in Shabbos (50b) and the ROSH here, however, write that although a Nazir has no intention to pull out his hair when he uses a comb, he may not comb his hair because it is a "Pesik Reishei" (inevitable) that hair will be pulled out. Why do they explain that combing is prohibited because of "Pesik Reishei"? They should explain the Gemara in the most straightforward sense, that one intends to remove hair through combing, as the Gemara here explains.

ANSWERS: The RIVASH (#394) explains that Rashi prefers not to explain the Gemara in the most straightforward sense because of the words of the Mishnah that follows. The Mishnah concludes that Rebbi Yishmael prohibits a Nazir from scrubbing his hair with Adamah (earth, a form of shampoo) because doing so removes the hair. The Mishnah clearly implies that a Nazir may not use Adamah because it is a "Pesik Reishei" that hair will be removed. Since the beginning of the Mishnah which discusses Chofef and the end of the Mishnah which discusses Chofef (with Adamah) both refer to an act of "Davar she'Eino Miskaven," it is logical to assume that the middle case -- combing -- is also a case of "Davar she'Eino Miskaven." Hence, the reason combing is prohibited is that it is a "Pesik Reishei."

This answer explains the words of Rashi. Why, though, does the Gemara give a different reason for the prohibition against combing the hair? (See Rivash there.)

(a) The KEREN ORAH explains that according to Rashi, the Gemara means that a person uses a comb to separate the hairs from each other, but not to remove the hairs from his head. Nevertheless, it is inevitable that some hairs will be removed from his head since there are always some hairs that are loose. Although the Nazir does not intend to remove those hairs but only to separate the hairs from each other, he may not comb his head because of the "Pesik Reishei." (This may be the intention of the Rivash as well.)

(b) The MAGEN AVRAHAM (OC 303:22) explains that Rashi is giving an additional reason, besides that which the Gemara gives, for why a Nazir may not comb his hair. The Gemara's reason applies only when the Nazir actually intends to remove hairs with the comb. Rashi's reason applies even when he does not intend to remove hairs. In such a case he is still prohibited from combing his hair when the comb is hard and will remove hairs beyond a doubt ("Pesik Reishei"). The Gemara does not give Rashi's reason because it is teaching that even when the comb is soft, the Nazir is prohibited from combing his hair when he intends to remove hairs.

(c) TOSFOS in Kesuvos (6a, DH Hai) and elsewhere cites the view of the ARUCH who asserts that an act of "Pesik Reishei" is prohibited only when the person who does the act benefits from it. If he does not benefit from the inevitable, prohibited outcome of his act (that is, it is a "Pesik Reishei d'Lo Nicha Lei"), it is considered a "Davar she'Eino Miskaven" and is not prohibited.

According to the explanation of the Aruch, perhaps when the Gemara says that the Nazir intends to remove the loose hairs, it does not mean literally that he intends to remove them, but rather that he merely benefits from their removal (in that it makes him look handsome). This might explain why Rashi and the Rosh write that combing is a "Pesik Reishei." (However, the Rosh in Shabbos (12:1) rejects the opinion of the Aruch. See also the Rosh in Shabbos (14:9) who maintains that the Aruch does not permit a "Pesik Reishei d'Lo Nicha Lei" in the case of any Isur other than the case of Melachah on Shabbos.)

(d) It is also possible that the Gemara is giving a reason for why a "Pesik Reishei" is forbidden according to Rebbi Shimon, who rules that a "Davar she'Eino Miskaven" is not prohibited. Rebbi Shimon agrees that when it is inevitable that a Melachah (or other prohibited outcome) will occur as a result of the person's intentional act, the person is considered as though he also has intention to do the resultant Melachah as well, and therefore he is liable.