1) OBSERVING ONE DAY FOR TWO SETS OF NEZIRUS
QUESTION: The Mishnah states that when a person accepts upon himself Nezirus "when I have a son," and then he accepts a 100-day Nezirus, if his son is born before day 70 (of his 100-day Nezirus), the Nezirus for his son "does not interrupt at all." If his son is born after day 70, the Nezirus for his son "cancels" ("Soser") his 100-day Nezirus.
TOSFOS explains that he loses nothing if his son is born before day 70. He does not need to observe any additional days other than the 100 days he accepted, because the 30-day Nezirus for his son is included ("Muvla") in those 100 days. If his son is born after day 70, the 30-day Nezirus is not included in the 100-day Nezirus and he must make up the 100-day Nezirus by observing additional days after the end of the 30-day Nezirus for his son.
This implies that it is possible for one day to count towards two different sets of Nezirus -- for his own Nezirus and for the Nezirus he accepted for his son. If this is correct, however, why, in the second case of the Mishnah in which the son is born after day 70, do the days of the Nezirus for his son which coincide with the days of the 100-day Nezirus (for example, day 71 to day 100) not count for both sets of Nezirus? Why in that case may he not count those days towards his own Nezirus, but rather he must make up another 29 days for his own Nezirus after he finishes the Nezirus for his son? If observing the laws of Nezirus on one day can count towards two sets of Nezirus, what difference does it make if the son's Nezirus is entirely included ("Muvla") in the time period of his own Nezirus?
Moreover, the Beraisa earlier (14a) states that when a person accepts two sets of Nezirus -- a 100-day Nezirus and a 30-day Nezirus to begin 20 days from the moment of his acceptance, he must observe a total of 130 days of Nezirus even though the Nezirus he accepted to observe after 20 days is entirely included in the Nezirus of 100 days. Why should he not be able to observe only 100 days to count for both sets of Nezirus?
(a) TOSFOS, who explains the Mishnah as described above, apparently understands the logic of the Mishnah's ruling as follows. A count of days of Nezirus must reach its completion which will enable the Nazir to bring his Korbanos. A day can be counted towards the days of Nezirus only if that day brings the Nazir closer to the point at which his Nezirus is completed (at which time he can bring his Korbanos). Accordingly, if the Nezirus for his son is included in his own Nezirus and his own count of 100 days is concluded after he concludes the Nezirus for his son, every day of his Nezirus -- including the days he observed for his son's Nezirus as well -- brings him closer to day 100, at which time he can bring the Korbanos for his Nezirus. However, if his son is born on day 71 and he counts day 71 towards his own Nezirus, day 100 of his own Nezirus will occur before the end of the Nezirus for his son. He will not be able to shave on that day since he still needs to conclude the Nezirus for his son. Since he cannot count day 71 -- the first day of Nezirus for his son -- towards his own Nezirus, he cannot count any of the days of the Nezirus for his son towards his own Nezirus. He must observe two separate periods of Nezirus -- the Nezirus for his son and then the days for his own Nezirus. After he concludes his son's Nezirus, he observes another 29 days of his own Nezirus after which he is able to shave.
According to this explanation, why is the father able to observe the days of Nezirus for his son within the days of his own Nezirus when the child is born on day 60? The conclusion of the days of Nezirus for his son will occur on day 90 of his own Nezirus, when he still has not finished his own Nezirus and will not be able to shave for the Nezirus of his son. Consequently, none of those days should count towards the Nezirus for his son! The answer is that he is able to shave on day 90 if he wants; although he is still in the midst of observing the period of his own Nezirus, since he accepted the Nezirus for his son first (he accepted upon himself to become a Nazir "when I have a son," and then he accepted upon himself to become a Nazir "from today"), that Nezirus takes precedence and he is allowed to shave at its conclusion, even though it concludes during the period he is observing for his own Nezirus. If he does shave, however, he will have to wait 30 days from that day before he may bring the Korbanos for his own Nezirus, because "Ein Taglachas Pachos mi'Sheloshim Yom" (he may bring the Korbanos for his Nezirus only after he shaves his hair which grew for 30 days). Hence, it is advisable that he not shave on day 90, but rather delay shaving until day 100 when he can shave and bring Korbanos for both his and his son's Nezirus.
Accordingly, both the days which he counts for his own Nezirus and for his son's Nezirus bring him closer to a completion and conclusion of the Nezirus, at which point he may bring Korbanos.
Tosfos addresses the second question posed above as well. When a person accepts upon himself Nezirus after 20 days and then accepts a 100-day Nezirus, why does he need to observe more than 100 days? Tosfos (13b, DH O Dilma) explains that when a person does not make his Nezirus contingent upon an unpredictable event but says, "I will be a Nazir after 20 days, and I will be a Nazir right away for 100 days," he knows that the 30-day Nezirus he accepted first will be completed within the 100 days of the second Nezirus. Had he wanted to be a Nazir for only 100 days, he would not have mentioned the Nezirus after 20 days in the first place (since it is included in the 100-day Nezirus). It must be that he meant that he will be a Nazir for 30 days, and -- in addition to those 30 days of Nezirus which begin after 20 days -- he will be a Nazir for another 100 days, for a total of 130 days. In contrast, when he makes the Nezirus contingent upon the birth of his son, he does not know whether that event will occur during or after the 100 days of his Nezirus, and thus he presumably intends for the Nezirus to be included in his 100-day Nezirus if the birth happens to occur before the end of the 100 days. If it occurs afterwards, it will be a separate Nezirus of 30 days.
(b) The ROSH cited by the SHITAH MEKUBETZES points out that according to the explanation of Tosfos, the words of the Mishnah, "she'Ein Taglachas Pachos mi'Sheloshim Yom," are unrelated to the Halachah which the Mishnah teaches. Why does the Mishnah need to mention how long the Nazir's hair must grow if the Mishnah is discussing a case of a Nazir who did not cut his hair? The Mishnah is not discussing a case of a Nazir who cut his hair and needs to observe days of "Gidul Se'ar," but rather a case in which the child was born before or after 70 days.
Tosfos (13b, DH l'Achar Shiv'im) addresses this question and offers a forced answer. Tosfos says that the Mishnah simply means to suggest that it is not worthwhile for the Nazir to shave after the Nezirus for his son if the Nezirus for his son is "Muvla" within his own Nezirus, since if he shaves after the Nezirus for his son he will have to wait extra days of "Gidul Se'ar."
The ROSH, however, explains the Mishnah in an entirely different manner because of this question. His text of the Mishnah does not include the words in the Seifa (as the text of Tosfos includes) that if the child is born after 70 days it is "Soser" his Nezirus. Rather, the Mishnah according to his text states that if the child is born after 70 days, it is "Soser Ad Shiv'im" -- it cancels the amount of days, from his 100-day Nezirus, between the day on which the child was born and day 70. For example, if the child was born on day 80, he loses 10 days (80 - 70). If the child was born on day 90, he loses 20 days.
The Rosh explains that the Mishnah certainly does not mean that the Nazir counts the days of the Nezirus of his son at the same time he counts the days of his own Nezirus. Rather, he always observes 130 days of Nezirus. If, however, his son is born before day 70, after he finishes counting Nezirus for his son, he must count 30 additional days for his own Nezirus, after which he shaves. If his son is born after day 70, he has less than 30 days to observe for his own Nezirus, and thus before he is able to complete his own Nezirus he must shave after he completes his son's Nezirus. As a result, he must add days to his own Nezirus because "Ein Taglachas Pachos mi'Sheloshim Yom." He must observe additional days of "Gidul Se'ar" (29 days for the completion of his Nezirus, and one day of "Gidul Se'ar") so that he will have enough hair-growth to shave and bring his Korbanos. If his son is born on day 71, he loses one day and thus he must add one day for "Gidul Se'ar." If his son is born on day 80, he must add 10 days of "Gidul Se'ar," and he must observe 30 days instead of the 20 days which remained of his 100-day Nezirus.
The Rosh's explanation is consistent with his own view expressed elsewhere. The Rosh earlier (13b) discusses the case of a person who accepts upon himself to become a Nazir when he has a son, and he also accepts to be a Nazir for 30 days. After 20 days pass, he has a son. The Halachah requires that he observe 30 days for the Nezirus for his son and then shave, and then return to his own Nezirus for the next 10 days. However, since he shaved after the 30 days of Nezirus for his son, he needs not only another 10 days for his own Nezirus, but an additional 20 days of "Gidul Se'ar" (see Insights there).
The Hagahah in Tosfos (13b, DH l'Achar) cites the Yerushalmi which explicitly states what the Rosh writes, that the Mishnah means that if the son is born on day 80 of the 100 days the Nazir loses 10 days, and if the son is born on day 90 the Nazir loses 20 days.
In summary, according to the Rosh, a person can never count one day towards two different sets of Nezirus.
(c) The HAGAHAH in Tosfos (13b, DH l'Achar) which cites the Yerushalmi interprets the Yerushalmi in exactly the opposite way of the Rosh. He explains that whether the son is born before day 70 or after day 70, the days of Nezirus for his son always count towards his own Nezirus, even though the Nezirus for his son continues beyond the last day of his own Nezirus. The Yerushalmi's text of the Mishnah is like that of the Rosh; the Mishnah states that if his son is born after day 70, it is "Soser Ad Shiv'im," which means that if the child is born on day 80 he loses 10 days, and if he is born on day 90 he loses 20 days. In what way does he lose 10 days? He must observe a total of 110 days of Nezirus, rather than 100 days which he would have had to observe had the child been born before day 70.
In summary, according to the Hagahah, one day of Nezirus always counts towards as many sets of Nezirus as needed.
According to this explanation, what is the intent of the Mishnah earlier (13b) which says that when a person accepts upon himself to observe Nezirus when a son is born and he accepts a 30-day Nezirus from now, and after 20 days a son is born, "he stops his own Nezirus and counts Nezirus for his son, and then completes his own Nezirus"? Why does the Mishnah say that he stops his own Nezirus to observe his son's Nezirus, and then he completes his Nezirus afterwards? The Nezirus for his son should count towards his own Nezirus, and the 20 days which passed before his son was born plus the first 10 days of the Nezirus for his son should constitute the completion of his own Nezirus!
The Hagahah actually asks this question on the Yerushalmi, and because of this question he offers a forced explanation in the Yerushalmi in order to reconcile the Yerushalmi with the explanation of Tosfos. However, perhaps Tosfos understands that when the Mishnah says that he "stops" his own Nezirus it means merely that he does not continue his own Nezirus exclusively and delay the Nezirus for his son until after his Nezirus is completed, as he must do in the case of the Reisha of the Mishnah, because by doing so he will need a total of 60 days of Nezirus. Rather, "he stops his own Nezirus" means that he starts his son's Nezirus right away, without actually stopping his own, and he has no Nezirus which is exclusively his own. "Afterwards he completes his own Nezirus" means that only after day 50 passes, when he has already completed 30 days of Nezirus for his son, does he bring the Korbanos for his Nezirus. It is called "Mashlim" ("completing" his Nezirus) since he delayed those Korbanos from day 30 until day 50 due to the observance of his son's Nezirus.
According to this explanation of the Yerushalmi, the question of the Rosh returns. In what way is the law of "Ein Taglachas Pachos mi'Sheloshim Yom" related to the case of the Mishnah? The reason why the Nezirus of his son lengthens the amount of time he must observe for his Nezirus is unrelated to the restriction against shaving after observing less than 30 days, since he does not shave after his son's Nezirus! It must be, as Tosfos answers this question according to his explanation, that the Mishnah is teaching that if he does not want to add more than 10 days when his son is born on day 80, he should not shave at the end of his Nezirus before the completion of his son's Nezirus. That is, he should not shave on day 100 but rather on day 110, because if he shaves on day 100 he will not be able to finish his Nezirus on day 110 because of "Ein Taglachas Pachos mi'Sheloshim Yom."