Question: According to Rabeinu Tam and Rabeinu Shmuel who require a size of an egg to accept impurity, how do we know that the Pasuk is teaching that the Shomer combines to bring impurity to the object? Perhaps the Pasuk is saying that it combines only to give impurity to other items (but not to bring it to the object itself)!

Answer: Since a Yad brings impurity to the object and gives it to other objects, as does a Shomer, regarding combining to do this it should also be the same as a Yad (which combines both to bring and to give impurity).

Question: Rebbi Eliyahu asked, how do we know that there is a concept of Yados regarding vessels? One cannot derive this from the concept of Yados found by seeds, earthenware ovens, and Neveilos, as these cannot become pure in a Mikvah!

Answer: It appears that this is from the derivation in Toras Kohanim, "And the one who touches them - including Yados." This possibly teaches that other vessels have Yados. If only this Pasuk were stated, I would think that it is referring to the items most similar to the context of that Pasuk. (This is why both this Pasuk and the Pasuk mentioned in the Gemara are required to derive all Yados.)

Question: On the contrary, it is more appropriate to compare impurity from its ability to become impure, as the fact that it cannot become impure is do the fact that it never had the ability to become impure in the first place!

Answer: One might say that the case is regarding a tree full of fruit that became detached from the tree, became able to become impure, and then was replanted.

Question: It is impossible to say that this is the case, as when a person would replant this fruit the original ability to become impure is nullified when it takes root. Even impurity is nullified in such a case, as the Mishnah in Terumos (9:7) says regarding growths of Terumah.

Answer: It is obvious to the Beraisa that they only become impure when they become detached, as Rashi explains that if one says that fruit that are attached are impure, he has made everything impure!

Answer (cont.): The Beraisa means that they cannot make the fruit able to become impure before they are detached, even regarding the fruit only becoming impure after they become detached.

Question: For the same reason that it is obvious regarding impurity (otherwise all produce would be impure when it is still attached) it should be obvious regarding the ability to become impure! We should say that if you say this, everything is already able to become impure when it is attached to the ground (and it is possible that it touched dead Sheratzim etc.)!

Answer: It is not so difficult if we will say that everything became able to become impure through rain that fell on the seeds (as the real issue is their impurity, not their being able to become impure, see Tosfos ha'Rosh).

Explanation #1: Rashi explains this is referring to an amount of meat the size of a bean or half an olive that has a Yad, and is together with an amount of food the size of an egg.

Question: This does not appear correct, as even if the food touched the half an olive (of meat) itself it would not become impure!

Proof #1: This is apparent from the Gemara earlier (24b) that says that the Torah testified regarding an earthenware vessel that even if it is full of mustard seeds, all of the seeds are impure (because they are in the airspace of the impure earthenware vessel).

Proof #1 (cont.): This implies that if it were not for the fact that the airspace of the earthenware vessel causes impurity, the mustard seeds would not become impure even though they are touching each other. (In other words, if the seeds would be in a regular vessel, the seeds would become impure through their contact with the vessel. However, the seeds in the middle of the vessel that are not touching any part of the vessel would remain pure!)

Proof #2 (cont.): The Mishnah in Chagigah (20b) states that a vessel combines whatever is inside it regarding Kodesh, but not regarding Terumah (and certainly Ma'aser and Chuin).

Proof #2 (cont.): The Gemara asks in Menachos (24a) if this law regarding the vessel combining its contents is specifically when the items are touching each other or not. If touching is considered to combine, it would seem obvious that the Mishnah in Chagigah (ibid.) is discussing a case where they are not touching, as if they were there would be no need for a special law regarding a vessel combining!

Explanation #2: It appears that meat the size of half an olive is connected to the food the size of an egg. However, it is not connected very strongly. If he would pick up the meat, the food would detach from the meat. Therefore, the Yad is only a Yad to the meat and not to the food.

Observation: According to Rashi who explains that any size food can become impure, it is unnecessary to say that it was connected to other food. Rather, the question is if it brings impurity to the meat (that is the size of half of an olive). However, regarding it making other items impure, even if one touched meat the size of an entire olive it would not cause impurity, as this would only be true if it was meat the size of an egg.

Observation (cont.): Even if it does not become impure if it is very small according to Torah law, one can say that the question is if it becomes impure according to Rabbinic law, as according to Rabbinic law even a small amount can become impure.

Explanation: The concept of Yad regarding impurity of the dead is derived from a Mah ha'Tzad from Neveilah and an earthenware oven.

Explanation (cont.): Just as a Neveilah does not cause impurity of an Ohel etc. If you will ask that a Neveilah is food, and therefore one should not be able to derive a dead person from food (as stated in Kerisus 21b), we can derive this anyway from an earthenware oven.

Explanation (cont.): However, one could ask that an eartheware oven is different as it becomes impure due to what is in its airspace (as opposed to a dead person or other kinds of impurity). The Tzad ha'Shaven (common ground) between Neveilah and an earthenware oven is that they make things impure and their Yad is like them etc.

Question: Why don't we see Dayo regarding Tumas Ohel? (In other words, both Neveilah and an earthenware ovens have nothing to do with Tumas Ohel. How can we derive that Yad applies to Tumas Ohel as well, if the sources of this law are items that do not show this applies regarding Tumas Ohel?)

Answer: Originally, we did not find Yad regarding serious impurity, and we therefore asked Dayo on Neveilah. (The Gemara earlier (118a) asked that we should not be able to derive Yad regarding Neveilah from other Yados, as a Neveilah can make people impure as opposed to other items where Yad applies. It ended up deriving Yad regarding Neveilah from a separate source.) However, now that we find Yad applies regarding serious impurity (i.e. Neveilah), as it is like the item itself, regarding a dead person a Yad should also be considered like the item (i.e. dead person) itself.