פירוש על נדרים 5:1

השותפין – that each one of them a house in the courtyard, and the courtyard that is in front of the houses, both of them are partners in it But at the time when the courtyard has the law of division/partition, and as such there will be four cubits in the courtyard to each and every house in front of the house, and there will remain from the courtyard another four cubits to this one (i.e., person) and four cubits to that one (i.e., person), in this everyone admits that both of them are forbidden to enter into the courtyard until they divide it, for since the law of division/partition is there. But Rabbi Eliezer and the Rabbis do not disagree other than regarding a courtyard that does not have the law of division, as the Rabbis state that each of them enters through his fellow’s [property], but Rabbi Eliezer ben Yaakov holds that there is a retrospective designation (i.e., the legal effect resulting from an action selection or designation or disposal of things previously undefined for their purpose/ברירה) and this one goes to his and that one goes to his.

Introduction In the time of the Mishnah, people’s homes opened into jointly possessed courtyards. The custom was to use the courtyard for various purposes, including cooking, grinding wheat and raising chickens. However, each resident could prevent the others from using the courtyard for such purposes. Our mishnah discusses a situation in which either both or one of the owners of the courtyard has taken a vow not to benefit from the other. The question is, can they still use the courtyard?

ושניהם אסורים להעמיד שם רחים וכו' – But Rabbi Eliezer ben Yaakov admits in all of these that the partners prevent each other, for it does not belong to permit for the reason of the retrospective designation, for since it is within his hand/power to prevent him, and if he doesn’t prevent him,it is found that he provides him benefit.

If joint owners [of a courtyard] made a vow not to benefit from one another, they may not enter the courtyard. Rabbi Eliezer ben Jacob says: This one enters his own property and this one enters his own property. If both owners of the courtyard vowed not to benefit from the other, according to the first opinion neither may enter the courtyard at all. As we learned above (4:1), one who is not allowed by vow to benefit from another, may not walk on his property. Since the property is jointly owned, each one would be entering the other’s property. Rabbi Eliezer ben Jacob holds that since in general both people can enter the courtyard, neither is really entering someone else’s property. At each point where he stands he could claim that this part is his. Therefore, both can enter the courtyard.

ופופין את הנודר למכור את חלקו – for we are concerned that after he sees his fellow entering, he will forget and will also enter. But when both are prohibited [from entering] we don’t concern ourselves, and specifically when he took a vow on his own not to enjoy benefit from his fellow is when we force him to sell his portion but if his fellow made him take a vow that he will not benefit from him, he is the victim of an unavoidable accident, and we don’t force him to see for what can he possibly do? But if you stated such, each partner should make his friend take a vow that he will not benefit from him in order that we can force him to sell his portion.

And both are forbidden to set up a mill-stone or an oven or raise chickens. Neither may use the courtyard for any of its normal uses. Rabbi Eliezer ben Jacob would agree with this, since putting any of these things in the courtyard requires the neighbor’s permission, and in this case, permission cannot be granted.

If [only] one was forbidden by vow to benefit from the other, he may not enter the court. Rabbi Eliezer ben Jacob says: He can say to the other, “I am entering into my own, and I am not entering into yours.’ If only one owner is prohibited by vow from benefiting from the other, he may not enter the courtyard. Again, Rabbi Eliezer ben Jacob holds that this is permitted.

They force the one who vowed to sell his share [of the courtyard]. In such a case, the one who vowed must sell his share of the courtyard, lest he come to use the courtyard, which even Rabbi Eliezer ben Jacob prohibits. However, this is only true if he himself swore not to benefit from his neighbor. If his neighbor swore that he should not benefit from him, he is not forced to sell his share of the courtyard.