Siman 10

One who slaughters with a knife from the accessories of an idol, and they performed a usage with it that was already forbidden as is written below in siman 139, and in a manner where it was not forbidden due to absorbed treifot—for example, they used it for cutting wood for an idol, or even if they used it with an absorption of treifa but they performed hagalah on it, and the prohibition is only due to usage for an idol and its prohibition is a prohibition of benefit—his slaughtering is permitted. It is not considered as benefiting from prohibitions of benefit, for regarding the prohibition of benefit from an idol, it is not called benefit, since the animal or the bird while alive is worth more than after the slaughtering. Regarding this benefit, it is called "one who causes damage," for the living creature while it is alive stands for two things: to raise offspring and also for eating, and after slaughtering it stands only for eating. And the females of living creatures have in them while alive also a third benefit: for milk and for eggs.

Therefore, even though slaughtering for other purposes is called a benefit and the end of an animal is for slaughter, and one who slaughters on Shabbat is liable for stoning if intentional and a sin-offering if unintentional, and it is among the primary categories of labor, for it is certainly called a "thoughtful labor" when there is some improvement in the labor even if there is also damage [Shabbat 106a]; nevertheless, regarding benefit from Avodah Zarah, it was not forbidden unless it is entirely an improvement. For in such a case the sages of blessed memory said [Avodah Zarah 48b]: what he improves in this, he damages in that, see there. For the prohibition of benefit from Avodah Zarah is not due to the category of labor, but rather because he benefits from it, and since against the benefit there is damage, it is no longer considered a benefit [this is the intent of the Tosafot Chullin 8a and all the Rishonim and the Achronim]. And you should know that it is so, for if he slaughtered with this knife when it was notched and the animal became treifah, it is obvious that it is permitted for benefit, for he damaged it completely. Yet on Shabbat, even in such a case, he is liable, for there is an improvement in that he removed it from the status of a limb from a living animal, and there is also the taking of a soul, which is a primary category of labor [Shabbat 75a].

And know that from the language of the Shas which says ibid. "a knife of idolaters, it is permitted to slaughter with it," it is clear that even ab initio it is permitted, and such is the language of the Tur and the Shulchan Aruch. Nevertheless, from the language of the Rambam at the end of chapter 7 of Laws of Idolaters, who wrote "a knife of idolaters that one slaughtered with, it is permitted because he is damaging," see there, it is clear that only ex post facto it is permitted. And one must reflect on our teacher, the Beit Yosef, for later in siman 142 he wrote according to the language of the Rambam, and here he wrote according to the language of the Shas and the Tur, see there. And it is possible that he follows his reasoning in his book Kesef Mishneh there, that the Rambam holds that the language "permitted" is not specifically ab initio, and therefore he was not precise with this language. And there is one who says that there it deals with a case where it requires hagalah [Shach subsection 3], and so it is implied from the words of our teacher, the Rema, there, see there. But regarding the words of our teacher, the Beit Yosef, it is impossible to say so, since he did not answer this way regarding the words of the Rambam, of blessed memory. Furthermore, it appears to me to distinguish that when there is another knife, certainly ab initio one should not slaughter with it, for even though there is no benefit in this, nevertheless it is a mitzvah to distance oneself from this; but when there is no other knife, it is permitted to slaughter with it ab initio. [And the Shas and the Tur, whose ruling is regarding the laws of slaughter, this is the explanation: a knife of idolaters, it is permitted to slaughter with it when there is no other, for when there is another, why should he use this? And the Rambam, who deals with the laws of idolaters regarding forbidden benefits, says that if they slaughtered with it, it is permitted. And the words of the Shulchan Aruch can also be explained thus, even though it appears that he did not intend this, as is proven from his words in Kesef Mishneh as I have written].

And specifically a healthy animal, but if he slaughtered a dying animal with the knife, the entire animal is forbidden, for this is a complete improvement and constitutes a benefit, as if he had not slaughtered it, it would have died. And so it is clear from the wording of our teacher, the Beit Yosef, below in siman 142, that even ex post facto the entire animal is forbidden. And so it is clear from the wording of the Rambam there, and the disposal of the benefit to the Dead Sea does not avail, for he follows his reasoning there where he wrote regarding one who took a shuttle from an asherah and wove a garment with it, that the entire garment is forbidden, and only when it was mixed with others is it permitted through disposal of the benefit to the Dead Sea, and here too it is similar. However, the Tur wrote in the name of the Rashba that disposal of the benefit to the Dead Sea is sufficient, and this is equivalent to the fee for a knife for slaughtering; and he holds that this is not called benefit from the essence of the prohibition, for the animal has already grown and lacks nothing except to make it fit through slaughtering. And in the name of the Rosh he wrote that even disposal of the benefit is not required for this reason, and it is not so compelling [see Shach subsection 5; and also the Ran ruled like the Rashba, and so wrote the Yam Shel Shlomo siman 11; and also in the wording of the Rambam, who wrote "it is forbidden" and did not write "it is forbidden for benefit" as in all the laws there, it requires study, and examine it closely].

One who slaughters with a knife belonging to Kutim that is saturated with non-kosher absorption must peel the place of the shechitah, because the place of the shechitah is considered like boiling and absorbs from the knife; and furthermore, even if we do not judge it as boiling, nevertheless, due to the pressure of the knife that presses against the neck, it absorbs [Gemara 8b]. And it is not only necessary if the knife is "ben yomo" from its use with forbidden food, but even if it is not "ben yomo"; for although that which is absorbed in vessels when it is not "ben yomo" is a "giver of a flavor that impairs" and is permitted, nevertheless, a typical knife has its fattiness smeared upon its surface, and it is like a forbidden substance in its essence [Rashba, Ra'ah, and Ran]. And more than a peeling is not required, for the heat of the place of the shechitah is less even than the heat of a "kli sheni," as the Tur wrote in siman 105, and it is obvious that it does not absorb more than the thickness of a peeling. And some say that this is specifically when it is known that the knife is "ben yomo," but when it is not known, and typical vessels are not "ben yomo," a peeling is not required and rinsing is sufficient [Tosafot and the Rosh], for the fattiness that is on the knife also becomes spoiled because of the iron, as it is the nature of iron to spoil, and this is not considered like "ben yomo." And the opinion of the Rambam and the Shulchan Aruch is that in any case a peeling is not required and rinsing is sufficient, because they hold that the place of the shechitah is considered cold; however, it requires rinsing, for behold, fattiness was wiped off upon it, and even though it was not absorbed into the meat, it is on the walls of the place of the shechitah, as it is impossible for the sides of the knife to be without fattiness [Rashi according to Rav Bar Bar Chana, whom the Rambam rules like, though Rashi ruled like Rav]. And for the halachah, we hold that it requires peeling, for such is the opinion of most of our teachers, and so all the great Acharonim agreed.

And it is forbidden ab initio to slaughter based on the reliance that one will peel it after the slaughter [Tur], for the general rule is that regarding anything that must be done after the slaughter, it is forbidden ab initio to rely on this before the slaughter, because we fear perhaps he will forget and not do it, as was written in siman 1. And so too, even according to the opinion of the Rambam, who only requires rinsing, it is forbidden to slaughter based on the reliance that he will rinse after the slaughter. And even though all meat requires rinsing before salting, nevertheless we fear perhaps he will roast the meat, and then it does not require rinsing, as was written in siman 76. Furthermore, the rinsing before salting is merely a general rinsing, whereas the rinsing here requires thorough scrubbing because of the fat [Ran]. And with a knife that was wiped very well, it is possible that it is permitted when it is not known to be ben yomo, for the reason that anything that is "imparting a foul flavor" is permitted ex post facto; and if so, regarding slaughter, it is possible that it is permitted ab initio, and it requires further study.

If they sharpened the knife with a whetstone or thrust it ten times into hard ground, it does not require peeling even if it was used within the day, because the place of the shechitah is not like a complete boiling heat, as has been written. Therefore, even though sharpening and thrusting are not effective for a complete boiling heat, as has been written in siman 121, nevertheless regarding the heat of the place of the shechitah we are not concerned that the knife will emit and cause absorption into the meat. With sharpening, it may be permitted even ab initio, but with thrusting only ex post facto [Shach, subsection 8]. And know that thrusting is only effective for a knife that has no pits on its sides, as has been written there. And there are those who permit even with thrusting ab initio [see Bach]. And in a case of pressing need where one has no other knife, according to all opinions it is permitted to perform shechitah with it ab initio even with thrusting alone [Rema]. And one should not say let us wait until after twenty-four hours so that the absorbed matter becomes tainted and we should not permit it ab initio, for it can be said, for example, that one needs the meat to eat today.

The Tur wrote: A knife with which one slaughtered a kosher animal, even though it is soiled with blood, it is permitted to slaughter with it another time. However, it is forbidden to cut something hot with it, but it is permitted to cut something cold by means of rinsing, that he should rinse it first. And since they slaughtered a treifah with it, it is forbidden to slaughter with it another time until he rinses it in cold water or wipes it with a hard substance. And we are now accustomed to wipe it well with the hair of the animal between every single slaughtering, and it is considered proper. And if he slaughtered with it without rinsing, he shall rinse the place of the slaughtering. And if he is accustomed to slaughtering treifot with it regularly, it requires thrusting ten times into hard ground. Thus far his words. And so wrote the Shulchan Aruch.

The explanation of the matter is that even though we hold that the place of slaughter is hot, as has been written, and if so, any knife with which one slaughtered once and is soiled with blood, we should have forbidden slaughtering with it another time because it would absorb the blood of the first, and blood absorbed from another place does not exit through meliha as has been written in siman 69; nevertheless, we do not say so. For we only say the place of slaughter is hot regarding a knife that was already treifa and emits into the meat, and the meat is only prone to absorb. But the opposite—that the knife should absorb from the heat of the place of slaughter—we do not say so, for the knife is hard to absorb and relative to it, the place of slaughter is considered cold [Rashi]. However, according to this reason, we should have required rinsing the knife so that the second slaughtering does not absorb from the actual blood that is on the knife from the first slaughtering. And from the Tur it is implied that rinsing is not necessary. Furthermore, regarding the reason that has been explained, there are those who disagree and hold that the knife also absorbs from the heat of the place of slaughter [Rashba in Torat HaBayit, page 76, subsection 9]. But for another reason we do not fear the absorption of blood, for the simanim are preoccupied with emitting their own blood, and since they are preoccupied with emitting, they do not absorb. For this is a great principle in matters of emission and absorption: that a thing which is emitting does not absorb at the time of the act, for it cannot do a thing and its opposite in one moment.

And that which he wrote, that it is forbidden to cut a hot item with it, is because the knife will emit into the hot item the blood absorbed within it from the slaughtering; therefore, even if he rinsed the knife it is forbidden. From this it is proven that also regarding the knife we say that it absorbs from the heat of the pressure of the slaughtering [and for this reason the Rashba disagrees with Rashi]. This law is an explicit Gemara [111b]. And also regarding the Rambam, of blessed memory, it is difficult, for he holds regarding the knife of gentiles that the pressure of the slaughtering is cold and rinsing is sufficient, as has been explained, yet he ruled in chapter 6 of Ma'achalot Assurot this law, that a knife with which one slaughtered is forbidden for cutting a hot item until one performs hagalah, see there [and Rashi himself wrote there that the pressure of the slaughtering is hot and the knife absorbs, see there] [and according to what the Ran wrote there, that according to Rashi it deals with a case without rinsing, it is well-settled]:

And it must be said that he holds that although the knife does not absorb much from the heat of the beit hashechitah such that it would have the power to also emit via the heat of the beit hashechitah—and therefore it is permitted to slaughter with it—nevertheless, it absorbs a small amount from the heat of the beit hashechitah, and that small amount it will emit in absolute boiling liquid. For the heat of the boiling liquid is so strong that it will force the knife to emit into it the small amount of blood absorbed in it from the heat of the beit hashechitah. And therefore, the Rambam indeed wrote there that ex post facto, if one cut boiling liquid with it, it is permitted, see there, because it is a light emission and the prohibition is only ab initio. And even according to the Rashba, who holds that the absorption of the knife is equal to the absorption of meat, nevertheless it appears that a kelipah is sufficient when they cut boiling liquid with it, for we have already explained that the heat of the beit hashechitah is lighter than the heat of a kli sheni and does not absorb more than a kelipah [Shach, subsection 14]. And therefore, also regarding boiling liquid, even though it requires hagalah, nevertheless even ab initio hagalah via pouring from a kli rishon is sufficient, even though it is not like a kli rishon, for it only emits a kelipah, since that which is absorbed is also only a kelipah. And in siman 68 and siman 105 these laws will be explained.

And that which he wrote, that it is permitted to cut cold food with it by means of rinsing, that he should rinse it first, it is simple that without rinsing there is actual blood present and it would be absorbed into the cold food by the pressure of the knife. And by means of rinsing it is permitted even though there is pressure of the knife. Therefore, even though with any forbidden knife it is forbidden to use it even for cold food until one plunges it ten times into the ground, as is written in siman 121, nevertheless here, where the absorption is light, rinsing is sufficient [Ran, end of chapter "Kol HaBasar"]. And it also teaches us that specifically rinsing, but wiping is not effective unless it is a thorough wiping and not a light wiping [ibid.]. And even if he slaughtered with it many times, it is permitted to cut cold food with it by means of rinsing [Shach]. And it is not similar to one who slaughtered a treifah, which will be explained, that rinsing is not effective when one slaughtered many, for there the prohibition is because of fat, but here it is because of blood, and blood slides off [ibid.].

And that which he wrote, that when one slaughtered a tereifah with it, it is forbidden to slaughter with it until he rinses it or wipes it with a hard substance, the reason is that with a tereifah, which is entirely forbidden, in addition to the blood upon the surface of the knife, the fat upon its surface is also tereifah. And regarding this we do not say "since it is occupied with emitting, it does not absorb," for only regarding blood do we say that since it emits blood it will not absorb blood, but not that it will not absorb fat, for the emission of blood is one thing and the absorption of fat is another. However, rinsing or wiping with a hard substance, which is like rinsing, is sufficient, and we do not fear the absorption that is within the knife because the knife is resistant to absorption, as I wrote in section 9. And according to those who disagree there, it is also permitted because the minimal absorption that occurs through the heat of the place of slaughter does not have the power to emit through the heat of the place of slaughter, but rather only through complete boiling, as I wrote in section 11.

And that which he wrote, that it is customary to wipe the knife with the hair of the animal between each and every shechitah, is for the reason that perhaps a tereifah will be found, and a thorough wiping with hair is effective because hair is stiff. And specifically regarding animals is this the custom, and not regarding fowl, because tereifot are not common among them. Furthermore, if they were to practice this with fowl, it would be a great burden to wipe with a stiff object between every shechitah, for wiping with their bodies is not effective since the feathers are soft and are not similar to hair [see Shach, subsection 18]. And even if a tereifah should happen to occur, there is no concern in this, for they generally rinse the chicken afterward, and consequently the place of the shechitah will be rinsed, and this is effective as will be explained before us [and also we are not accustomed to eating the trachea and esophagus of fowl and we throw them away].

And regarding that which he wrote, that if he slaughtered without rinsing he should rinse the place of slaughter, they challenged him: for since it was found to be treifah, it has absorbed the fatty substance of the forbidden, and it is similar to the knife of idolaters where he himself ruled that it requires peeling [Rashal and Bach and Shach subsection 19]. However, in truth, the words of the Tur are well-settled, for regarding the knife of idolaters, according to the Rambam it does not require peeling; and granted that in that case we do not rule like him because it absorbed much of the forbidden, but in one who slaughtered a treifah where a small amount of the forbidden is absorbed in it, it can be said that according to everyone rinsing is sufficient [Taz subsection 16]. Furthermore, there the absorption was by means of actual boiling heat, which is not the case with the heat of the place of slaughter, for the heat is light as I have written. And it is necessary to say that the Tur distinguishes in this way, for he wrote: "And if he is accustomed to slaughtering treifot in it regularly, it requires ten thrusts into hard ground," thus far his words. That is to say, and he may slaughter with it ab initio; and behold, for boiling heat, thrusting does not avail, as I wrote in siman 121. Rather, it is certainly because the heat of the place of slaughter is light, as I wrote in section 7, even regarding the knife of idolaters, and all the more so here where the absorption is also by means of the place of slaughter. And for this reason, the Tur was lenient regarding the slaughter of a treifah one time with the rinsing of the place of slaughter. However, for the law, several of the poskim disagree with this and hold that it requires peeling.

In every place where one must rinse the knife because of fat, such as when one slaughtered a treif animal and the like, the Rishonim wrote that when one rinses with cold water, one must first remove all the fat until one pours water over the knife and the water flows from its beginning to its end and from its end to its beginning; for if one does not remove the fat beforehand, the water is obstructed and cannot flow [Sefer Mitzvot Gadol and Hagahot Maimoniot chapter 17 of Ma'akhalot Assurot in the name of the Ritzba]. And it implies that with hot water there is no concern for this, for the heat removes the fat. And know that in siman 91 it will be explained that in a place where kelipah is required and they did not peel it, one must place against the kelipah; see there.