מתני׳ שומרת יבם בין ליבם אחד בין לשני יבמין רבי אליעזר אומר יפר רבי יהושע אומר לאחד אבל לא לשנים רבי עקיבא אומר לא לאחד ולא לשנים

MISHNA: With regard to a widow waiting for her yavam to perform levirate marriage, whether she is waiting for one yavam, if her late husband had only one brother, or whether she is waiting for two or more yevamin, if he had several brothers, Rabbi Eliezer says: A yavam can nullify her vows. Rabbi Yehoshua says: If she is waiting for one yavam, he can nullify her vows, but not if she is waiting for two. Rabbi Akiva says: A yavam cannot nullify her vows, regardless of whether she is waiting for one yavam or for two or more.

אמר רבי אליעזר מה אם אשה שקנה הוא לעצמו הרי הוא מיפר נדריה אשה שהקנו לו מן השמים אינו דין שיפר נדריה

The mishna then elaborates: Rabbi Eliezer said: Just as with regard to a woman he acquired for himself through betrothal, he nullifies her vows, so too with regard to a woman acquired for him from Heaven, i. e., the yevama, isn’t it logical that he should be able to nullify her vows?

אמר לו רבי עקיבא לא אם אמרת באשה שקנה הוא לעצמו שאין לאחרים בה רשות תאמר באשה שהקנו לו מן השמים שיש לאחרים בה רשות

Rabbi Akiva said to him: No, if you say that a husband can nullify the vows of a woman he acquired for himself, over whom others have no authority, shall you also say that this is the case with regard to a woman acquired for him from Heaven, over whom others have authority? If there are two yevamin, each yavam has equal authority with regard to her vows.

אמר לו רבי יהושע עקיבא דבריך בשני יבמין מה אתה משיב על יבם אחד אמר לו אין היבמה גמורה ליבם כשם שהארוסה גמורה לאישה

Rabbi Yehoshua said to him: Akiva, your statement applies in a situation with two yevamin, but how do you reply to Rabbi Eliezer in the case of one yavam? Rabbi Akiva said to him: A yevama is not the full-fledged wife of the yavam in the in the way that a betrothed woman is her husband’s full-fledged wife, and the yavam is not empowered to nullify vows at all.

גמ׳ בשלמא רבי עקיבא סבר אין זיקה ורבי יהושע סבר יש זיקה אלא רבי אליעזר מאי טעמיה אי יש זיקה אין ברירה

GEMARA: The latter two opinions in the mishna make sense: Rabbi Akiva holds that the levirate bond is not substantial. Since the obligation of levirate marriage does not create a marriage-like bond between the yavam and the yevama, a yavam cannot nullify the vows of the yevama. And Rabbi Yehoshua holds that the levirate bond is substantial, so that if there is only one yavam, the yevama is considered his wife, allowing him to nullify her vows. However, with regard to Rabbi Eliezer, what is his reason? Even if he holds that the levirate bond is substantial, there is, nevertheless, no retroactive designation. Since it has not yet been established which of them will be her husband, how can either of them nullify her vows?

אמר רבי אמי כגון שעשה בה מאמר ורבי אליעזר סבר לה כבית שמאי דאמרי מאמר קונה קנין גמור

Rav Ami said: It is a case where one yavam has already performed levirate betrothal with her. According to Beit Hillel, levirate betrothal does not have the full force of a regular betrothal, but Rabbi Eliezer holds like Beit Shammai, who say: Levirate betrothal effects a full-fledged acquisition just like a regular betrothal.

ורבי יהושע אומר לך הני מילי בחד יבם אבל בשני יבמין לא מי איכא מידי דכי אתי אחוהי אסר עליה בביאה או בגיטא ומפר ורבי עקיבא סבר אין זיקה

But Rabbi Yehoshua would say to you, Rabbi Eliezer, in response: That statement, that levirate betrothal effects a full-fledged acquisition, applies only to a case with one yavam, but with two yevamin it is not so. The Gemara explains why it cannot be a full-fledged acquisition where there is more than one yavam: Is there anything like this sort of betrothal that when his brother comes, he can render the betrothed woman forbidden to the one who performed levirate betrothal by engaging in sexual intercourse with the yevama, thereby performing levirate marriage, or by giving her a bill of divorce, thereby disqualifying her from levirate marriage, and nevertheless the betrothed can still nullify her vows? Since this betrothal can in essence be nullified, it cannot be viewed as betrothal with regard to nullification of vows. Rabbi Ami completes his analysis: And Rabbi Akiva holds that the levirate bond is not substantial at all, and there is no marital bond between a yevama and her yavam until the levirate marriage is consummated.

ולרבי (אליעזר) [אלעזר] דאמר מאמר לבית שמאי אין קונה אלא לדחות בצרה מאי איכא למימר

The Gemara challenges Rabbi Ami’s interpretation of the dispute: And according to the amora Rabbi Elazar, who said that levirate betrothal, according to Beit Shammai, does not effect a full-fledged acquisition except in that it removes a rival wife from being considered substantially bound to the yavam while she is a yevama, what can be said? Only the relatives of the betrothed yevama are then forbidden to the yavam.

הכא במאי עסקינן כגון שעמד בדין ואיתחייב לה מזונות וכדרב פנחס משמיה דרבא דאמר כל הנודרת על דעת בעלה היא נודרת

The Gemara answers: Here we are dealing with a case where the yavam stood in court in judgment after the woman demanded that he marry her and he was obligated by the court to provide her sustenance. And this is in accordance with that which Rav Pineḥas stated in the name of Rava, who said: Any woman who vows, that which she vows is contingent upon her husband’s consent. Since under these circumstances the yavam must provide for the yevama he betrothed, he is authorized to nullify her vows.