The Gemara answers: Here, with regard to impurity, it is different, as the Merciful One states in the Torah: “And he defile his consecrated head” (Numbers 6:9), which indicates that even one whose naziriteship is dependent only upon his head, i.e., one who has completed his naziriteship other than shaving, is liable to receive lashes if he contracts impurity. The Gemara raises an objection to the statement of Rabbi Yosei, son of Rabbi Ḥanina, from a baraita: A nazirite whose days are completed is forbidden to shave, and is forbidden to drink wine, and is forbidden to contract impurity from corpses. And if he did shave, or drink wine, or contract impurity from corpses, he incurs the forty lashes administered to one who violates a Torah prohibition. This baraita clearly states that he is flogged for any of the three prohibitions, which is a conclusive refutation of the statement of Rabbi Yosei, son of Rabbi Ḥanina.

MISHNA: In the case of one who said: I am hereby a nazirite when I will have a son, and he added: I am hereby a nazirite from now for one hundred days, and he then began observing the one hundred days of his naziriteship, if a son is born to him up to seventy days from the start of his naziriteship he has not lost anything. He pauses from the observance of the naziriteship of one hundred days and observes the thirty-day term for his son. He then completes the thirty or more days left of his initial naziriteship. However, if his son is born after seventy days, this negates the first seventy days, and he must observe a full hundred days after he completes the naziriteship for his son. The reason is that here, he is unable to merely complete the remaining days of his initial naziriteship after shaving at the completion of the naziriteship for his son, since shaving cannot be performed after a period of less than thirty days.

GEMARA: Rav said: The seventieth day itself counts for here and for there, as the last of the seventy days of his term of naziriteship as well as the first day of the naziriteship for his son. The Gemara questions Rav’s statement. We learned in the mishna: If a son is born to him up to seventy, he has not lost anything. This seems to include the seventieth day as well. And if it enters your mind that it counts for here and for there, not only has he not lost anything, but he even gains a day, so why would the mishna state: He has not lost anything? The Gemara answers: Rather, by right the mishna should not have taught: Up to seventy he has not lost anything, since if the son is born on the seventieth day he actually gains, as stated above, but due to the fact that it is taught in the last clause of the mishna: After seventy it negates seventy, in which case he does lose, the tanna therefore teaches the first clause with the contrasting expression: Up to seventy he has not lost anything.

The Gemara asks further: Come and hear a statement that contradicts Rav’s opinion from the last clause of the mishna: If the son is born after seventy days, it negates the first seventy days. If, as Rav stated, one day can count for both terms, then the final day of the thirty-day term for his son also counts toward his hundred-day term, meaning that there will be thirty days remaining for a full hair growth; in that case, why should he forfeit the first days? The Gemara answers this: What is the meaning of: After? It means after, after. The mishna is referring to the second day after the seventieth, the seventy-second day, so that there do not remain thirty days for his hair to grow.

The Gemara asks: But according to this explanation, what would be the halakha if a son is born on the day that actually comes after the seventieth, the seventy-first day; so too, would Rav say that it does not negate the previous days, because he has thirty days remaining to grow his hair? If so, why does the tanna specifically teach: If he is born up to seventy he has not lost anything? The same would hold true even for a case where he was born on the day after seventy as well, as didn’t you say that it does not negate? Rather, one must learn from this that: After, means the actual day after, the seventy-first day, and likewise conclude that the mishna is difficult for Rav. The Gemara concludes: Indeed, learn from this that the tanna of the mishna disagrees with Rav.

§ The Gemara asks: And Rav, in accordance with whose opinion did he say his halakha? Since the tanna of the mishna disagrees with him, which tanna does he follow in ruling that one day may be counted for two different observances? If we say that he stated the ruling in accordance with the opinion of Abba Shaul, as we learned in the Tosefta (Mo’ed Katan 2:9): With regard to one who buries his dead three days before a pilgrimage Festival, the rabbinic decree of seven days of mourning is voided for him, i.e., once the Festival begins, he no longer observes the prohibitions and customs of the first seven days of mourning. Since he has mourned for three days, the Festival voids the remainder of the seven days.

The baraita continues: If he buried his dead eight days before a pilgrimage Festival, the rabbinic decree of the restrictions of thirty days of mourning is voided for him as well. Since he already observed one day of this type of mourning he need not complete the entire period, and it is therefore permitted for him to cut his hair on the eve of the pilgrimage Festival in honor of the Festival. But if he did not cut his hair on the eve of the pilgrimage Festival, it is prohibited for him to cut his hair after the pilgrimage Festival, until thirty days of mourning have passed.