Rabeinu Tam's Opinion: Rabeinu Tam states that the buyer can even back out of the deal after he paid for the field. This would be in a case where the acquisition is not done by means of the money paid, but rather in a place where the sale is done through writing up a contract.

Our Gemara is coming to teach us not only that it is possible, but that it is also permitted to back out of the deal. Being that the buyer will probably be losing his money as he realizes that the people with a claim on the field will probably try to seize the field from him, he can back out of the deal. He does not even receive a "Mi she'Para" (a curse usually given to those who pay money and then back out of a deal).

This is apparent from the Gemara in Bava Metzia (49b). The Gemara there states that there was a person who bought a donkey from his friend. He heard that it was going to be seized by Parzak, the second-in-command in the area. He went before Rav Chisda, who told him that just as they decreed that pulling an object is an acquisition for a guardian (that he becomes obligated to watch the object), so too they decreed that it is the point of acquisition for buyers.

The Gemara there does not say that he would be liable to receive the "Mi she'Para" curse from Beis Din, like the Gemara indeed says is the law in a different case in Bava Metzia (ibid.). This is because the sages only decreed one should receive a "Mi she'Para" curse if he backed out of the deal because of price fluctuations (not if he will lose all of his money).

Explanation: This that Abaye says "he could back out" really means "he is permitted to back out." This is similar to the terminology used in Bava Metzia (49a) regarding a person who says to a friend that he is giving him a present. Although Abaye really should have stated explicitly that this is permitted, he used the word "could" to match the end of his statement, where he says that if he already took possession of the field he "cannot" back out of the deal.

Implied Question: Abaye's statement is not in conflict with the opinion in Bava Basra (44b) that states that if a seller sold a field without Achrayus and it was later revealed that he had stolen the field, the buyer can get his money back.

Answer: In our Gemara, as long as the people complaining that they should receive the field did not yet take the field, it is clear that the opinion in Bava Basra (ibid.) will admit that the buyer cannot back out of the deal.

Question: This is a difficult statement. What is Abaye asking when he says "When is it considered that he made a "Chazakah" - "took possession" (of the land)?" Don't we already know the definition of a Chazakah from an explicit Mishnah in Bava Basra (42a), that says that "if someone locked, fenced in, or made an opening so that he could enter the land even slightly, this is called a Chazakah?"

Tosfos' Answer: Abaye's question is where a person already paid for land, how much of a Chazakah does he need to make? He answers that once the person steps on the borders of the land this is already called a Chazakah, even though it is less of an action than locking it up or making a fence. This is because it is combined with the giving of money (he therefore needs less of an action).

Rivam's Answer: The Rivam explains that Abaye is communicating the following idea. If Reuven sold a field to Shimon and did so with a complete Kinyan, until Shimon does a Chazakah on the field that shows that he will not back out on the deal, he may still back out of the deal despite the fact that he made a Kinyan.

The reason for this law is that we know the Rabbanan enacted that a person can retract a deal as long as the deal is still being discussed between the two parties, because a person's mindset in buying and selling is to be able to back out whenever a deal is still being discussed.

Here, too, Abaye is stating that a person's mindset is to back out of such a deal if people start trying to claim the land before he is able to establish a Chazakah. However, once he establishes a Chazakah on the land he can no longer back out of the deal.

Abaye's question regarding when is the Chazakah established means, what is this point of Chazakah that a person has in mind that at this point he will no longer retract the deal? Abaye tells us that this is when he steps on its borders to gather information regarding the needs of the land.

Explanation: According to the first version of Abaye, this law does not apply to someone who buys a field with Achrayus. This is because a person who buys a field with Achrayus only has in mind to buy property that is totally free of complaints regarding its ownership.

This is despite the fact that the field would be returned to him if the seller indeed had stolen it, as we explained earlier (referring to Tosfos #2 above, see Maharsha) in a case when the field was stolen and he purchased it without Achrayus. This is because such a buyer is simply not interested in getting involved in a court case with judges.

Question: I am not sure why the Gemara did not originally answer that the case is where the women with the Kesuvos of three hundred and two hundred wrote to the woman who had a Kesuvah of one hundred that they have no claim on her for twenty five of the estate. [This would result in her taking that twenty five, and leave the next seventy-five to be split amongst the three, resulting in the first woman taking fifty as stated by the Mishnah.]

Explanation: This is not exactly like the first case of the Mishnah, as here each collects according to how much they are owed.

Rabeinu Chananel's Opinion: Rabeinu Chananel explains that this statement of the Mishnah is connected to the last case of the Mishnah. [In that case everyone happened to collect according to what they were owed, even though it was not because of the law that the division is done according to the money owed (see Maharam Shif).]

Implied Question: The reasoning for this statement is not clear (see Tosfos Yom Tov on the Mishnah).

Implied Question: My mentor did not know how to explain what the Mishnah is coming to teach us [according to the Gemara's explanation].

Comment: The Rach states that in this argument we rule according to the opinion of Rebbi.

Explanation: It cannot be that Rebbi means that when the estate has three hundred zuz that all of these women (with a Kesuvah of one hundred, two hundred, and three hundred) will collect one hundred each. This would be simply unjust.

When Rebbi says they split the estate evenly, he must mean that each hundred they split evenly. Therefore, the estate is divided in six parts: the woman with a Kesuvah of one hundred receives one sixth, the woman owed two hundred receives two sixths, and the woman owed three hundred receives three sixths.

Each woman receives a portion based on the money that is owed her until each one receives her entire Kesuvah. This is a just solution.

This that Rebbi states that he argues with Rebbi Nasan is regarding the first and middle cases of the Mishnah.

However, the last case in the Mishnah where the estate has three hundred and the woman with a Kesuvah of one hundred takes fifty, the woman with a Kesuvah of two hundred takes one hundred, and the woman with a Kesuvah of three hundred takes one fifty is not argued on by Rebbi. Whether the estate receives this amount at one time or at two different times, Rebbi agrees that the law is that each one receives an amount according to what she is owed.

First Proof: We find a Mishnah in Bava Kama (36a) where Rebbi Shimon discusses an ox that is worth two hundred which gores another ox of similar value, and the body of the dead ox is worth nothing. In such a case, the value of the ox that gored is split, with each (owner of each ox) receiving one hundred.

If the ox that gored gores another ox worth two hundred, the last person takes one hundred of the value of the goring ox, the owner of the previous victim takes fifty and the owner receives fifty.

If the ox continued to gore a third ox worth two hundred, the owner of this ox receives one hundred, the previous victim receives fifty, and the original victim's owner and the owner of the goring ox have twenty five. The Mishnah is established to be according to the opinion of Rebbi Akiva who says that each victim becomes a partner in the ox (which is why he keeps losing half of his stake in the ox whenever his ox keeps goring). The law follows Rebbi Akiva's opinion.

This division of money is in accordance with the stake each owner has in the ox. This is why Rebbi's opinion in our Gemara must also be that each woman receives an amount from the estate based on the amount of her Kesuvah. This way the opinions of Rebbi Akiva and Rebbi, both of which are codified in Halachah, are not contradictory.

Second Proof: The Beraisa in Bava Basra (124a) states that Rebbi said that a firstborn son receives a double portion in improvement in his father's estate, even if they happened after his father died. If they inherited a loan document (that their father was owed money), the firstborn takes a double portion of the money owed.

This shows that Rebbi holds that divisions are according to the amount owed. If one were to suggest that the payment split the improvements equally, this would prove contradictory to Rebbi's opinion here.

It therefore makes sense to firmly state in accordance with Halachah that Rebbi holds that the division is done according to the amount of money owed to each person. In this way all of the Halachic rulings stated above are in agreement.

Question: It is possible to differentiate between our Gemara and the Gemara in Bava Basra (ibid.). The Gemara there is not discussing a case of people who are owed money, but rather each inheritor actually owns part of the land/estate. A firstborn owns twice as much land, and therefore keeps the amount that his portion went up in value.

However, in our case there is a lien on the entire estate due to each woman who is owed a Kesuvah. The lien remains on the entire estate, even due to the woman who is owed only one hundred, until she receives her full hundred. [This is therefore different than the case above, where the division of improvement is based on each inheritor owning his set part of the estate.]

Explanation: The Gemara asks this question (against Rabah and not Rav Hamnuna) based on the knowledge that it will follow up this question with the next question of the Gemara regarding the end of the Beraisa.

Explanation: The Gemara is assuming the case is akin to the case of an ox that was for plowing but is now being sold for slaughter. If it was originally bought for the purpose of being slaughtered and is going to be sold as much, there is no novelty in teaching that it is divided proportionate to the investment.

The Gemara is therefore assuming such a case, and is asking a strong question on Rav Hamnuna.

Explanation: They became partners with the intent that if they will only profit by exchanging their coins for better coins that they will split the money equally and not be sticklers about dividing the profits based on the percentage each invested.

This that they received "new" coins is not to exclude old coins, as it is apparent from many places in Bava Metzia (i.e. 45b) that old coins are often better and more accepted than the newest currency. Rather it is contrasting new currency with very old currency.

Introduction to Question: The Gemara in Bava Basra (13a) states that Rav Yehuda asked the following question on Rav Huna. Rav Yehuda observed that Rav Huna held there is no law regarding the division of partnerships that one partner can present the other with an ultimatum (in specific situations) that he must either buy him out or the other partner will buy him out.

Rav Yehuda therefore asked Rav Huna, if a firstborn son and a regular son inherit from their father a slave or an unkosher animal, what should they do?

Rav Huna replied that the servant should switch off working one day for the regular son and two days for the firstborn son.

Question: Rabeinu Tam asked, why did Rav Yehuda have a problem specifically in a case involving a firstborn son and a regular son? The problem should apply with two regular sons as well!

Rabeinu Tam's Answer: Rabeinu Tam answered that indeed Rav Yehuda understood that when there are two regular sons the slave will switch off working one day for each. However, he did not understand what to do in the scenario of a firstborn son and a regular son.

If he will work for the regular son for one day and then work two days for the firstborn son, the firstborn son will end up getting more than double his share.

Let us assume there is a far away city that it takes one day of travel (roundtrip) to reach, and there is a lot of good business and cheap wares to be had there. The regular son who only has the slave for one day at a time cannot send him there, while the firstborn son who has him for two days at a time can send his slave to that city. This enables him to profit from the division of the slave much more than his brother.

Rebbi's Answer: Rebbi explains that this is why Rav Yehuda had more of a question regarding a firstborn son and a regular son. Everyone agrees that if partners buy an ox with the intent of using him to plow and this is what they use him for, they split the benefit evenly.

This is why the Gemara asks what should be done, as if they split evenly the firstborn will not get his double share. Rav Huna answered that he does receive a double share, as he works for the regular son one day and the firstborn for two days.

This is unlike the case of partners in an ox for plowing, as there the profit is divided as that was the working knowledge of the partnership. However, regarding a firstborn so where this reason does not apply, each one takes according to his share.

Implied Question: The Mishnah could not have stated a simple case involving two women, even though the argument between the Tana Kama and Ben Nanas seems applicable there as well.

Answer: Nevertheless, we would not have known from an argument involving two people the concept that an oath to one is like an oath to one hundred.

Now that the case is with four women, we learn that the reason that the first wife does not swear to the third wife is because she already swore to the second wife, as explained in the Gemara.

Question: This seems difficult. If this is the reason, why did the Mishnah say four women when it could have said a case of only three? A case of three would also tell us the lesson that an oath for one is like an oath for one hundred!

Answer: It is possible that in a case of three we would think that the first wife does not have to swear to the third wife. As she is the last wife, there is not much to suspect because the first wife already swore to the second wife.

The third wife might have already received her Kesuvah and doesn't swear to anyone else. It is therefore possible that we would think the Rabbanan simply were not stringent to require the first wife to make an oath to the third wife in this case.

If the third woman would swear, like the case (in our Mishnah) where there is a fourth woman involved, the third woman would certainly not have received her Kesuvah at this point. Without our Mishnah, we would think that the first wife should also have to swear to her. This is why our Mishnah stated a case involving four women (and now we know for certain the concept that an oath to one is like an oath to one hundred).