CLAIM OF BAR METZRA
The law of bar metzra (requiring a potential buyer to forgo his purchase of land in favor of the adjoining property owner who wants to buy the land at the same price) is a rabbinical innovation to give special rights to allow one with a connection to the property to acquire it. The main reason for the halacha of bar metzra is to allow the neighbor to maximize the potential of his property, by making use of the proximity or expand boundaries. While the Rabbis attached to this law the pasuk of “you should do the good and the straight in the eyes of HaShem” (Devarim 6:18), that is not a halachically binding source. Therefore, in cases of doubt, we should not employ this rule when it is not clearly mandated, thereby uprooting the Torah-level law that the buyer has attained ownership of the property and cannot be forced to give it up. On the other hand, if the community accepted this law with a cherem (a ban) the efficacy of the cherem is like that of Torah law.
In his comments to Hilchos She’chainim of Rambam (14:5), Magid Mishnah explains the concept of דינא דבר מצרא—the right of first refusal of a neighbor to purchase a field which is for sale. He notes that the Torah provides guidelines for a person to perfect his character and his conduct, all in fulfillment of the Torah’s directive “to be holy” (Vayikra 19:2). As Ramban explains in his Commentary on the Torah (ibid.), the Torah commands that we sanctify ourselves by abstaining even from things that are technically permitted, in order that we not be preoccupied with trying to indulge in physical pursuits. The Torah also commands us to “Do that which is correct and good in the eyes of G-d” (Devarim 6:18), which teaches us that the Torah expects that we conduct ourselves in a manner whereby other people see us as being pleasant and proper. Now, the Torah cannot specify every action which leads to this outcome, because this guideline regulates every time and every place where a person interacts with others. Our sages, however, have provided several standards of conduct along these lines. Some of these they established as law, while others are recommended whenever they are possible (לכתחילה), while others are labeled as pious behavior.
The statement of Rav Yehuda in the name of Rav in the Gemara is that if someone grabs control of a field which is ownerless ((הפקר, this acquisition is valid even if the field is situated between two brothers or between two partners. Although it is obvious that the brothers or partners have a strong interest to take that field for themselves, the third party who took it acted impudently, but we do not remove it from him. The rule of דינא דבר מצרא does not apply to a field which is ownerless in this case. The brothers or partners had made no effort to acquire the field until this point, so we dismiss any claim they might now have. Rav Nachman, however, contends that the brothers or partners may assert their claim even now, and they may take the field from the third party based upon the rule of דינא דבר מצרא.
Shulchan Aruch (C.M. 175:56) rules according to R’ Yehuda in the name of Rav, that we do not use the rule of דינא דבר מצרא when obtaining a field which is ownerless. Sm”a explains that this rule may yet be applicable if the neighbor is willing to pay for the field, and the one who acquired it might be obligated to sell it to the neighbor. Sm”a himself is ambivalent about this point, because once the third party acquired the field legally, he might be able to keep it, and not be required to accept payment from the neighbor. Prisha, however, rules that the neighbor may offer to pay for the field, and the land must be surrendered to him.
