In the previous Mishnah we discussed the status of utensils found in Jerusalem. Our Mishnah continues with this topic and deals specifically with a knife used for slaughtering that was found, as well as with several related laws.
A knife found on the fourteenth of Nisan:
A knife found on the fourteenth of Nisan, the day on which the Pesach offering is slaughtered - "shochet bah miyad" - one may slaughter with it immediately. To appreciate the novelty here, an introduction is needed: even though utensils found in Jerusalem are generally not considered tamei, and we do not assume that the knife has contracted tumah, nevertheless in matters of sacrifices additional care is taken, and one is particular to immerse utensils in a mikvah before using them.
Even so, a knife found on the fourteenth of Nisan, the day on which everyone slaughters the Pesach offering, may be used immediately. The reason: we may assume that the person who lost it immersed it the day before, so that the sun would set and it would become tahor at nightfall of the previous night, and it would thus be fit for slaughtering the Pesach offering on that day. This assumption is reasonable, since many people do exactly that.
If, however, the knife was found on the thirteenth, the day before the time of the Pesach slaughter - "shoneh u'matbil" - he immerses it again. Even though it was most likely already immersed, it must be immersed once more, since it is possible that it was never immersed in a mikvah. The immersion is performed so that on that night, with the onset of the fourteenth, it will become tahor at sunset.
The law of the kofitz:
A kofitz is a type of hatchet, a utensil designed to break bones and to make a coarser cut, through the bones and limbs of a slaughtered animal - a butcher's tool. Regarding this utensil, even if one wishes to use it for slaughtering, we learned that whether it was found on the thirteenth or on the fourteenth, it must be immersed again.
The reason we do not rely on an earlier immersion even on the fourteenth: there is no certainty that the kofitz was immersed before the fourteenth, since it is not normally used for slaughtering but for breaking the bones of the meat, and with the Pesach offering it is forbidden to break the bones. It therefore stands to reason that it was not used for the Pesach offering at all.
The Gemara's question - the Chagigah offering:
The Gemara asks: it is true that the kofitz was not used for the Pesach offering itself, but along with the Pesach offering a Chagigah offering was frequently brought on the afternoon of the fourteenth, and with the Chagigah offering it is permitted to break the bones. If so, why not assume that the kofitz was immersed on the thirteenth, so that it had sunset and is fit for use for the Chagigah on the fourteenth?
The Gemara's answer - the case of the Nasi:
The Gemara explains that the Mishnah is dealing with a unique case: the Nasi - whether the king or the head of the Sanhedrin - was on the verge of death on the thirteenth of Nisan. The halachah is that if the Nasi dies, all of Israel are obligated to take part in his funeral and are liable to contract tumah thereby, and then the Pesach offering would be brought in a state of tumah, which is permitted in such a situation.
The situation is therefore in doubt: it is not known whether he will die or not, and consequently it is not known whether the utensils will need to be immersed. Here the two utensils differ:
The knife: it will certainly be needed, for without a knife there is no slaughtering. There is therefore only one doubt here - perhaps the Nasi will die, in which case no immersion will be necessary, since it will be permitted to use utensils that are tamei when everyone is tamei. Since there is only one possible outcome that would exempt him from immersion, a person will go ahead and immerse the knife on the thirteenth.
The kofitz: here two doubts are involved - perhaps no immersion is needed because the offering will be brought in a state of tumah, and perhaps the kofitz will not be needed at all because no Chagigah offering will be brought. The Chagigah offering is not brought in every case: even if the Nasi does not die, a small group of people does not need it, since the Chagigah comes to supplement the meat when there is not enough, and in a small group that is not necessary.
Therefore, with the kofitz there is reason to assume that it was not immersed, and because of these two doubts it must be immersed again even on the fourteenth.
The fourteenth that falls on Shabbos, and an item found on the fifteenth:
The Mishnah continues: if the fourteenth falls on Shabbos, one may slaughter immediately even with a kofitz. The reason: a person does not immerse utensils on Shabbos, and therefore we assume that the owner of the utensil took care of the matter in advance and immersed it on the thirteenth. And even though one cannot bring a Chagigah offering on a Shabbos that is the fourteenth, we assume that he attended to the immersion beforehand so that he would be able to use the kofitz for other offerings on the fifteenth.
Similarly, if the utensil was found on the fifteenth, which is Yom Tov, one may slaughter with it immediately, even with a kofitz, since on Yom Tov too utensils are not immersed, and so it was certainly immersed beforehand.
A kofitz attached to a knife:
In any case, a kofitz that is attached to a knife has the same status as the knife. Therefore, even in the ordinary case, when it is found on the fourteenth that falls during the week, when the knife may be used immediately because we may assume that it was immersed the previous day for the sake of the Pesach offering - if the kofitz is attached to it, we say that the same thing happened to it as well: it was immersed together with the knife on the previous day, the thirteenth, and it is therefore tahor and fit for use on the fourteenth.
In summary: In this Mishnah we learned that a knife found on the fourteenth of Nisan is fit for slaughtering immediately, on the assumption that it was immersed the previous day for the sake of the Pesach offering, whereas a knife found on the thirteenth requires an additional immersion. A kofitz, which is not normally used for slaughtering but for breaking bones, must be immersed on both days - and this is because the Mishnah is dealing with a case in which the Nasi was on the verge of death, and with the kofitz there are two doubts (perhaps the offering will be brought in a state of tumah, and perhaps no Chagigah offering will be brought at all) as opposed to a single doubt with the knife. We also learned that on a fourteenth that falls on Shabbos and on the fifteenth, which is Yom Tov, days on which utensils are not immersed, one may use even a kofitz immediately, and that a kofitz attached to a knife has the same status as the knife.
From here we learn how much the Sages based the laws of purity on presumptions and assumptions drawn from the way the pilgrims and those slaughtering in the Beis HaMikdash conducted themselves, and in the next section we will continue our study of the laws of the Mishnah.