Commentary for Bava Kamma 3:9

And according to Rabbi Eliezer, why does he call it a primary category? The Gemara is trying to determine the difference between an av and a toldoh, a derivative of the av. According to the Rabonon if one does an av and a toldoh at one time , he is only liable for one chatos, but according to R’ Eliezer he is liable for two חטאת קרבנות, if so, what is the difference between an av and a toldoh? Tosafot is suggesting that there seems to be a very simple distinction. When one violates Shabbat by doing m’lochoh intentionally, he is liable for capital punishment. In order to be subject to capital punishment one must be forewarned by witnesses at the time of the transgression. Tosafot will attempt to prove, that when one is warned, even when doing one of the toldos, the witnesses must inform him of which av this is a toldoh. If so, then the difference between an av and a toldoh is that the warning must always name the av that he is violating even when doing a toldoh.
If you ask: Let us say that the difference between an av and a toldoh is as far as the warning is concerned, because one has to be warned, even when doing a toldoh, from which av this toldoh is derived? As the Gemara says in Chapter Tolin (Shabbat 138a), one who put wine through a strainer, for which m’lochoh do we warn him? Rovo says it is a derivative of borair, selecting R’ Zeira says it is a derivative of m’rakaid, sifting. We see that the witnesses must mention as they warn, from which av the toldoh is derived. Even according to R’ Eliezer there is a great difference between avos and toldos. At the time of warning one must always identify the av from which the toldoh is derived.
Tosafot will give us an alternative understanding of the Gemara in Tolin (Shabbat 138a) that does not require that the av be mentioned each time one is warned for violating a toldoh.
And we can answer: The explanation of the Gemara’s question is as follows:
There is no question, that if one is warned not to do the toldoh that he is liable. The Gemara was only asking,if the witnesses warned by mentioning an av, instead of the toldoh, which av would be the correct one, that would make him liable?
Rabbah says he must be warned that he is violating borair, but if he was warned that he is violating m’rakaid he would be exempt.
Since the warning was technically incorrect, he may have assumed that the witnesses were ridiculing him, and he is exempt.
However, if they warned him by saying that he should not strain, without mentioning any av, he is liable.¹Some question this answer of Tosafot. For even if we were to assume that Tosafot is correct, and the Gemara in Tolin, is not insisting that the witnesses must always cite the av, even so, the Gemara does say that if you did mention the av it is a valid warning. So the original question remains, why didn't the Gemara answer that the difference between an av and a toldoh is that, if you mention the proper av when warning, the violator is liable, even though they did not cite the toldoh at all. Whereas, if you cite a toldoh other then the actual one he is committing, the violator is not liable. There are those who answer, that if we hold that an av is not required when warning, then there is nothing special about the use of an av when warning. The reason the use of the av is effective is only because of the similarity between the av and the toldoh. Hence, if witnesses cited a toldoh while the violator was committing an av, he would also be liable if the toldoh cited is similar to the av. There would not be any difference between an av or a toldoh.
In this first answer, Tosafot has said that the Gemara quoted to prove that one must mention the av when warning doesn't really prove that point. Tosafot now answers the question, even if we should assume that our initial understanding of the Gemara in Tolin is correct, and the Gemara does say that one is always required to cite the av, even when warning one who is committing a toldoh.
And there is an alternative solution: That, is exactly what our Gemara means when it answers, that which was important when constructing the Mishkan is called an av, and it is required to warn one who is committing a toldoh with the name of that av.
(See Maharam for a thorough analysis of the various approaches to the next sentence in Tosafot. We will adopt the Maharam’s approach, that the word ועוד is a copyist’s error and should be deleted).
Maharam explains that Tosafot has a problem with his second answer. If Tosafot is correct that one does have to mention the av at all times, and that is the intention of the Gemara that says, that which was important in the Mishkan is considered an av and must therefore be specifically mentioned by the witnesses at the time of the warning, why does the Gemara have to tell me the criteria of an av? The Gemara should have simply answered that we have to mention the av when warning. The criterion of an av is not the issue at all. Tosafot sets out to prove that it was necessary to mention the criterion of an av here and it would not have been sufficient for the Gemara to say that one must include the av in a warning.
The Gemara in Shabbat (73b) is discussing one who grafts a tree.
According to Tosafot (ד"ה משום) understanding of that Gemara the conclusion of the Gemara is that if the witnesses warned the perpetrator by mentioning either the av of sowing seeds or planting a sapling, it is an effective warning. Now, in the Mishna that lists all the avos planting and not sowing is mentioned. It would seem that it is not necessary to mention the av in the warning, because we see that even if the witnesses mentioned planting, it would be an effective warning. That is why, Tosafot says, the Gemara did have to mention the criterion of an av. This is to demonstrate that planting a sapling is also an av even though it is not specifically mentioned in the list of avos. Once we know the criteria, we realize that a particular activity may be an av despite the fact that it is not on the list of avos.
Tosafot in anticipation of the question, why did the Gemara have to mention the criteria of an av, the Gemara should have simply said that one must use an av when warning?
For we find that if one commits a toldoh of planting a sapling, such as grafting a tree, or of cooking, it is not necessary to mention the av, sowing or baking,² Sowing seeds and planting a sapling are almost identical, and they are both considered avos. The Gemara in Shabbat says that the reason the Mishna list sowing and not planting is because the Mishna chose to list the avos according to what is necessary to produce bread. The same is true of the relationship of baking and cooking. Both are avos, even though only baking is listed. Baking is what pertains to the production of bread. Tosafot is pointing out that planting and cooking are both avos, even though they are not listed among the avos. and if the witnesses mention in their warning, the toldoh planting or cooking, the perpetrator is liable. We see from this ruling that planting a sapling and cooking have the status of avos because they fit the criteria, and even so, the Mishna does not mention them in perek k’lal godol (Shabbat 73a).

Thus we read: that which was [a] significant [labor] in the Tabernacle, [the Sages] characterized [it as] a primary category, [and] that which was not [a] significant [labor] in the Tabernacle, [the Sages] characterized [it as] a subcategory. Tosafot presents two different versions of the text. On the surface it appears that there would be some difference between the two texts. However, Tosafot in Shabbat (96b) says that there is no difference between the two texts quoted here in Bobo Kamo. See Maharshal, who inserts a third text into our Tosafot, because of this problem. We shall learn the Tosafot according to Maharam, who suggests that there is a difference between the two texts quoted here by the Tosafot. According to Maharam’s understanding we must say that the Tosafot in Shabbat and Tosafot here do not agree about the interpretation of the first text.
This is our text: That type of work which was significant in the construction of the Mishkan is called an av, that type of work which was not significant in the construction of the Miskon is called a toldo.
And according to this text, it comes to exclude some types of m’lochoh that were not significant even though they were used in the construction of the Mishkan, they are toldos and not avos, even though they were used in the construction of the Mishkan, as we find in Perek Bameh Tomnin (Shabbat 49b): They, the Levites who transported the Mishkan, raised planks from the ground to the wagons, which is hachnoso, bringing in, from the ground which is a public domain to the wagon which is a private domain, as opposed to hotzo’oh, carrying out from a private domain to a public domain. Carrying out is an av, bringing in is a toldoh. And handing from one wagon to the next, as the wagons are arranged along the public domain, is also a toldoh. These two are toldos even though they were used in the transport of the Mishkan and that is because they were relatively insignificant. We see that for a type of labor to be considered an av it is not enough for it to have been used in the transport of the Mishkan, it is required that it was significant in the Mishkan.
At this point, it appears that in order to be classified as an av there are two qualifications,
a) It was used in the construction or the transport of the Mishkan.
b) That it was a significant m’lochoh. We will reserve judgment on this conclusion, as will be explained later. See note¹ This is very puzzling. It seems that Tosafot is saying that according to this, second text, two criteria are required, but according to the first text, two criteria are not required only one. This contradicts our simple explanation of the first text of Tosafot and is the basis of the various disagreements about the proper understanding of Tosafot. Maharam suggests that our Tosafot holds that according to the first text, there is actually one criterion, significance. Were we to find a m’lochoh that we would consider significant, even if it were not used in the construction of the Mishkan, that would be an av. According to this explanation of Tosafot we are compelled to say that when the Gemara mentions, that which was in the Mishkan, it does not mean to exclude a type of work which was not in the Mishkan, it means that, even though it was used in the Mishkan, it must be significant in order to be classified as an av. Having been used in the Mishkan is not sufficient to be classified as an av. Ultimately; significance is the only criteria for classification as an av.
There are those who have the following text: Those types of labor which were in the Mishkan and are significant are called an av, those types of labor which were not used in the construction of the Mishkan and are not significant are called a toldoh.
According to this text, it must be said, that two criteria are required, used in the construction of the Mishkan and significance, but if the type of labor is significant, but was not used in the Mishkan, or the reverse, it was used in the construction of the Mishkan, but was insignificant, it is a toldoh.¹ This is very puzzling. It seems that Tosafot is saying that according to this, second text, two criteria are required, but according to the first text, two criteria are not required only one. This contradicts our simple explanation of the first text of Tosafot and is the basis of the various disagreements about the proper understanding of Tosafot. Maharam suggests that our Tosafot holds that according to the first text, there is actually one criterion, significance. Were we to find a m’lochoh that we would consider significant, even if it were not used in the construction of the Mishkan, that would be an av. According to this explanation of Tosafot we are compelled to say that when the Gemara mentions, that which was in the Mishkan, it does not mean to exclude a type of work which was not in the Mishkan, it means that, even though it was used in the Mishkan, it must be significant in order to be classified as an av. Having been used in the Mishkan is not sufficient to be classified as an av. Ultimately; significance is the only criteria for classification as an av.