and if not, they will be unable to walk, but will have to cross over to the other side of the river. Therefore, no advantage exists to cutting down the trees that block part of the river.

The Gemara cites a related incident: Rabba bar Rav Naḥman was going on a boat and saw a certain forest that was located right on the riverbank, as its trees had not been cut down to make room for the pullers. He said to those who were with him: To whom does this forest belong? They said to him: It belongs to Rabba bar Rav Huna. Rabba bar Rav Naḥman said: This is reminiscent of the verse: “And the hand of the princes and the rulers has been first in this faithlessness” (Ezra 9:2), because a renowned scholar is acting improperly. Rabba bar Rav Naḥman said to them: Cut down, cut down to clear a path.

Rabba bar Rav Huna arrived and found that his forest had been cut down. Since he was within his rights not to cut down his trees, as explained above, he grew angry and pronounced a curse: He who cut down this forest should have his branches cut down. The Sages said: Although he was unaware of the identity of the perpetrator, the Sage’s curse was nevertheless fulfilled, and consequently all the remaining years that Rabba bar Rav Huna was alive, the seed of Rabba bar Rav Naḥman did not last, as his children, his branches, died in his lifetime.

Rav Yehuda says: All participate in the payment for the construction of the city wall, and this sum is collected even from orphans, but not from the Torah scholars. What is the reason for this? The Torah scholars do not require protection, as the merit of their Torah study protects them from harm. By contrast, money is collected for the digging of a river or a well for drinking water, even from the Torah scholars.

The Gemara adds: And we said this halakha only if the town inhabitants do not go out in a crowd to perform the work themselves but pay workers to act on their behalf. But if they go out in a crowd, Torah scholars do not have to join them, as Torah scholars are not among those who go out in a crowd to perform work in public view.

Rav Yehuda says: With regard to the digging of a river, i.e., the periodic deepening of a riverbed to prevent it from blocking up, the lower ones, i.e., those who live by the bottom of the river, must assist the upper ones in digging it and fixing it, as those located at the bottom of the river stand to gain from any work performed down to their houses. But the upper ones do not need to assist the lower ones, as the reverse is not the case. And the opposite is true with regard to the digging of a ditch to remove rainwater. In that case, those who live higher up are interested in the operation and therefore must help the lower ones, but the latter need not aid the higher ones in doing so in the upper area.

The Gemara comments: This is also taught in a baraita: If there were five gardens that draw their water requirements from one spring and the spring became damaged, all must help fix it with the owner of the upper garden, near whose garden the damage occurred. As a result of this ruling, the owner of the lower garden fixes it with all of them in the above case, and fixes it for himself if the damage occurred in the lower area. And similarly, if there were five courtyards that would run off water into a single sewer and the sewer became damaged, all must help fix it with the owner of the lower courtyard, near whose courtyard the damage occurred. The result is that the owner of the upper courtyard fixes the sewer with all of them and fixes it for himself if the damage affected his courtyard alone. This is in accordance with Rav Yehuda’s ruling.

Shmuel says: One who takes possession of an open space left along a riverbank for the purpose of loading and unloading in order to plow and plant there during the time that it is temporarily unused is impudent. As for removing him, we do not remove him, as this piece of land is considered ownerless. And nowadays, when the Persians write to one who acquires land alongside a river: Acquire for yourself the field up to the portion of the river itself where the water reaches a horse’s neck, we even go as far as to remove him from the plot of land, as it belongs to the owner of the field.

Rav Yehuda says that Rav says: One who takes possession of land that is located between the land of brothers or between the land of partners and causes them trouble is impudent. As for removing him, we do not remove him, as they have no real claim against him. And Rav Naḥman said: We even go as far as to remove him, as one should not do anything that harms another. And if the complaint against him is due to the halakha of one whose field borders the field of his neighbor, as they owned fields bordering on this one, we do not remove him.

The Sages of Neharde’a say: Even if his claim was due to the halakha of one whose field borders the field of his neighbor, we still remove him, as it is stated: “And you shall do that which is right and good in the eyes of the Lord” (Deuteronomy 6:18). One should not perform an action that is not right and good, even if he is legally entitled to do so.

With the above halakhot in mind, the Gemara asks: If the stranger came to consult with one of the owners of the fields, and said to him: Shall I go and acquire the field, and the latter said to him, go and acquire it, as I will raise no objection, is it necessary to perform an act of acquisition with him to solidify the agreement? Or perhaps his mere promise is sufficient and it is not necessary? Ravina said: It is not necessary to perform an act of acquisition with him, while the Sages of Neharde’a say: It is necessary to perform an act of acquisition with him. The Gemara concludes: And the halakha is that it is necessary to perform an act of acquisition with him.

The Gemara adds: Now that you have said that it is necessary to perform an act of acquisition with the neighbor for the right to purchase the field, if he did not perform an act of acquisition with him and purchased the field, and the field increased or decreased in value, the price fluctuation occurs in the domain of the owner of the bordering field. The buyer’s purchase is considered a purchase on behalf of the neighbor, who then reimburses the buyer.

Accordingly, if this buyer bought it for one hundred dinars and the field was worth two hundred dinars, in order to determine how much money the neighbor must give him, we determine why the owner sold the field to the buyer at this price: If he sells to everyone at that cheap price, the neighbor gives the buyer one hundred dinars and takes it, as the neighbor could have bought it for this sum himself. But if the owner does not sell to everyone at this price and this buyer was given a discount, the neighbor gives the buyer two hundred dinars, the market value of the field, and takes it.

In the converse case, if he bought it for two hundred dinars and the field was worth one hundred dinars, the Sages understood that the neighbor can say to the buyer: I sent you to act for my benefit, but not to act to my detriment. Since the field will not remain in your possession, you are effectively my agent, and I am not prepared to pay more than its market value due to your mistake. Mar the Elder, son of Rav Ḥisda, said to Rav Ashi: This is what the Sages of Neharde’a say in the name of Rav Naḥman: There is no exploitation with regard to real estate, as land has no fixed value, and therefore it cannot be said that the buyer overpaid, and he is given whatever sum he spent.

The Gemara discusses a related case: If one sold to another a beit se’a of land in the middle of his property so that the buyer is surrounded on all sides by the seller’s fields, we see what type of land it is: Whether the land is superior-quality land or whether it is inferior-quality land, his sale is a valid sale, as it is a distinctive piece of land. In that case, the seller’s neighbors cannot object, as their fields do not actually border on this plot.