Commentary for Bava Kamma 4:26

For concerning the primary category [of ritual impurity], it impurifies a person and vessels.¹ A person who comes in contact with the source of tumoh becomes tomay and a vessel that comes in contact with an av becomes tomay. This does not mean that the person who became tomay through contact with an av can then bring tumoh to vessels. This is the correct text, and not the text “a person and clothing”.
For that expression implies that the person becomes tomay and causes his clothing to become tomay as he is wearing them. This is not true in the case of a dead rodent, semen and one who has been in contact with a corpse. They cause a person to become tomay, he becomes a Rishon, a first level of tumoh, but the clothes he is wearing do not become tomay. Since the wearer is only a Rishon and not an av, his clothing which are treated as vessels do not become tomay. As the Gemara says vessels (and clothing) can only become tomay from an av.²The situation to which Tosafot is referring, where the clothing do become tomay is an exception, and they only become tomay if the wearer is presently in contact with the source of the tumoh. For example, a person is in contact with a bed that was slept on by a zov or a needoh. While he is in contact with the bed, his clothes become tomay. When he separates from the bed and puts on another set of clothing they do not become tomay.
The Gemara has stated that an av of tumoh does not make its toldoh as itself. The toldoh has a reduced level of tumoh. It can only cause tumoh to foodstuff, but not to people and vessels. Although this is generally true for an av coming in contact with a person and with most utensils, there is an area where this is not true and the utensil will have a degree of tumoh as great as the av.
And if you ask: There is a tomay mais, a person who came in contact with a corpse, who causes a metal vessel to have the same degree of tumoh as the tomay mais himself, for we have a rule that the sword is the same level of tumoh as the corpse.³This is based on a verse in Parashat Chukas where the Torah speaks of a corpse as חלל חרב chalal cherev, literally the corpse of the sword. Chazal understood that this expression is used to teach us that the metal sword has the same degree of tumoh as the corpse. According to most Rishonim including Tosafot, this means that any metal vessel that comes in contact with a corpse or one who has been in contact with a corpse has the same degree of tumoh as the source from which he received the tumoh. The Rambam has a different understanding of this rule. We see that there is a toldoh of tumoh which has the same level of tumoh as the av. Tosafot points out that although the statement is generally true, there still is a difference between a tomay mais and the metal vessel with which it comes in contact. And we can answer: the metal vessel is still not entirely like the tomay mais, because that metal vessel will not cause a second metal vessel to become tomay, as the tomay mais does, as Rabbeinu Tam deduces at the beginning of Masechet Oholos.

The Sages taught: three primary categories. The Gemara asked a question: do the derivatives of damagers have the same laws as the avos? Now, the Gemara introduces a lengthy Braita that explains all the avos of shor and how they are derived. It seems as if the Gemara forgot to answer the question. Tosafot explains:
The Gemara interrupted its flow by citing this Braita, so that eventually he can explain, using this Braita as a basis, which are their toldos that are not like the avos, of which Rav Papa spoke.

But with [a horn] attached, say [that in] all [cases the legal status] is [that of] a forewarned [ox]. If we only had a verse that spoke of an unattached horn, we would say that the difference of tam and muad applies only to an unattached horn,
but when goring with an attached keren, I would say it is totally,¹ Totally is the literal translation. Here it is used in reference to time. It is always a muad. even the first time, muad. Tosafot tells us the practical difference that would result from what I might have thought: That one must pay full payment even the first time. This requires some explanation. At this point in the Gemara full payment for an attached keren is not mentioned in the Torah. That I might have thought that there is reason to pay in full, is not an adequate reason to require full payment. There must be some means of deriving a new rule, to require a payment that is not mentioned in the Torah. As we have already seen in Tosafot (2a ד"ה ולא) the Gemara later (5b) discusses the possibility of learning one av from the other. It is that Gemara that Tosafot uses to search for a source for the new ruling that an attached keren must make full payment.
The Gemara there concludes that all of the avos could be known, had the Torah only written bor and one other av. The Gemara there goes on to explain why the Torah did in fact write all of the Avos. There is one exception, keren, which may not be able to be derived from bor and one of the others. The Gemara says that the derivation of keren depends on a dispute among the amoraim. One holds that we could not learn keren from the other avos because all the others are initially muadim, it is usual for them to damage, whereas keren is not. It is therefore less likely to be liable, and we therefore cannot derive keren from the others. There is a second opinion there, that keren is more likely to be liable than the other avos, because of all the avos, it is the only one that harms intentionally. This amoro views the characteristics of keren as more likely to be liable than the others, so the others can be used as a source for keren. Tosafot will now show us how our Gemara which says that I would think that an attached keren should initially be a muad should be viewed in light of the Gemara on (5b).
And if you ask: From where would we derive that an attached keren makes full payment?
Tosafot suggests two possible sources for the attached keren, first: if from the unattached keren by a kal v’chomer and say that if the unattached keren is liable then the attached keren should certainly be liable? Then it should be sufficient² One of the rules of kal v’chomer we will learn about later in the Masechet is dayo דיו, it is sufficient to establish a new financial obligation with the kal v’chomer, but we cannot create a greater financial obligation based on a kal v’chomer that uses a lesser obligation as its source. For example in the case we are discussing, if we were to learn attached keren from unattached keren, which pays only half, we cannot conclude that an attached keren should pay more than half. That would be creating a greater payment from a lesser payment and kal v’chomer cannot do that. to give it the rule of an unattached keren and it should only pay half. The second possible source for an attached keren: If you want to learn attached keren from the other avos, as the Gemara says on (5b) that all the avos could be derived from bor and one of the others, that makes sense according to the one who says that keren is stronger than the other avos and is more likely to be liable, because keren has intent to destroy, and even keren can be derived from the other avos, as Rabbeinu Tam has explained that the opinion referred to on (5b) as saying keren is stronger, is actually the one who is mentioned later on (15a) as the one who holds that half payment of keren is a financial obligation, for he holds that ordinary oxen are not assumed to be guarded. That means that we cannot assume that they will not gore others and that there is no need to take measures to prevent them from goring. Rather, we must anticipate the possibility that they might gore, and one is responsible to prevent them from doing so. When he does not take those measures, he is liable for not fulfilling his responsibility.
According to this opinion the likelihood of attached keren damaging is no less that the other avos and we could derive the attached keren from the other avos. As opposed to a financial obligation because of his negligence of not guarding his oxen to prevent them from goring. The one, who holds that half payment is a fine, believes that essentially one need not take precautions to prevent oxen from goring. The torah’s insistent on half payment is a fine, not a financial obligation. The differences between the nature of the obligation, financial or fine will be discussed later in the Gemara. However, according to the one who says that half payment is a fine,³As opposed to a financial obligation because of his negligence of not guarding his oxen to prevent them from goring. The one, who holds that half payment is a fine, believes that essentially one need not take precautions to prevent oxen from goring. The torah’s insistent on half payment is a fine, not a financial obligation. The differences between the nature of the obligation, financial or fine will be discussed later in the Gemara because he holds that ordinary oxen are assumed to be guarded, and it is not necessary to take precautions to prevent oxen from goring, an attached keren cannot be derived from the other avos, as the Gemara says later on (5b), if you put bor together with any one of the other avos, the other avos could be derived from the combination,⁴ See Tosafot 2a, ד"ה ולא, note 1, for an explanation of how any of the avos can be derived from a combination of bor and one of the others. with the exception of keren, because one can refute the attempt to learn it from the other avos by arguing that it is not a fair comparison, since all the other avos are initially muadim, which means that it is the norm for them to cause damage as opposed to keren, which is assumed to be guarded, and not likely to cause damage.
We are now faced with the problem of understanding how according to the one who holds that half payment is a fine, our Gemara says that I would say that an attached keren is fully liable? There seems to be no source for such a conclusion.
Tosafot question is based on the understanding that when the Gemara says “I would say” that attached keren pays in full, is that the conclusion would be correct. Thus, Tosafot has attempted to show why that conclusion would in fact be correct. In Tosafot solution, he will say that this understanding of “I would say” is not necessarily so. “I might say” can mean that I might erroneously say.
And one can answer: That according to the one who says half payment is a fine, and that ordinary oxen can be assumed to be guarded, that which the Gemara says: but as a far as an attached keren, I might say that it is initially a muad and pay in full even the first time it damages, do not mean to say that a special verse is actually needed to teach me that attached keren is not a muad, and that if not for the verse I would correctly conclude that an attached keren is required to make full payment.
If one were to follow the regular systems of deriving one av from another, one could not logically reach the conclusion that an attached keren must make full payment, as we have already explained in Tosafot question. Rather, what is meant is the tanna needed to teach us by citing proof from a verse, that an attached keren as well is included in the term “goring”, so that you might not erroneously conclude that the term “goring” is limited to only an unattached keren, such as the iron horns of Tzidkiyah, but with an attached keren, it is initially the norm for an ox to damage, ror.and we could learn from bor and one of the other avos that attached keren is initially liable for full payment. To avoid making such an error the Braita cited the verse of “the horns of a r’aim are his horns”, with them he shall gore etc. This shows that goring with an ordinary attached keren is included in the term goring. There is no room for a possible error.

And the Torah teaches us, in passing, a concept. By using different verbs to describe the goring of a person as opposed to the goring of another animal, the Torah is teaching us that there is an inherent difference between killing a person and killing an animal. A greater effort and viciousness is required to kill a person. Therefore if an animal is muad to kill people, it is automatically muad to kill animals, but if the animal is muad to kill other animals it is not muad to kill people.
Tosafot points out that there seems to be a Gemara later that contradicts our conclusion. On (37a) Rav Papa clearly says that an animal that is muad to kill people is not muad to kill animals. Tosafot will attempt to reconcile this apparent contradiction.
And even according to Rav Papa who says later in Shor Shenogach Daled V’hay (37a) that a muad to kill people ordinarily is not muad to kill animals,which seems to contradict our Gemara and the lesson taught by the Braita,that is only when he killed only three people, by doing that he does not become muad to kill animals, but if he gored a person, an ox and a donkey which are three species he becomes muad for all including people.
However, if he gores an ox, a donkey and a camel, he does not become muad for people, even though he is muad for all animals, even according to Rav Papa as the Gemara says there (37a). That according to Rav Papa an ox who killed three different animals is a muad for all animals. The lesson of the Braita is still in effect, animals are more readily killed than humans. Tosafot offers a second solution to this contradiction:
And R’ M’nachem explained that the Gemara means to say as follows: An animal that is muad for people, who was a muad for everything including animals, and he retracted from animals, he saw an animal three times and did not attack it, but he remained a muad for people, there was no evidence that he retracted from killing people, remains a muad for animals, for the retraction from killing animals is inconclusive, as long as he remains a muad for people.
However, a muad for everything, people and animals, who retracted from killing people, is no longer muad to kill people, for his retraction from killing people is a retraction. According to this answer as well, we see that an animal is more likely to kill animals than humans, therefore his retraction from killing animals is inconclusive as long as he remains muad for people, but his retraction from killing people is a retraction even though he remains a muad for killing animals.

As one who consumes with the tooth. Why is tooth referred to as golol? Rabbeinu Chananel explains that the word golol is related to tooth as we see in Ezra 6, “rows of marble stone.” We see that golol is used to describe marble. For a tooth is similar to marble stone. We therefore translate “as the golol consumes”- as the tooth consumes. The word y’vaer is used to describe the activity of the tooth, so too, the verse in the Torah u’vee’air refers to the activity of the tooth.