יתר על כן אמר ר' אליעזר בן יעקב לא ישא אדם אשה במדינה זו וילך וישא אשה במדינה אחרת שמא יזדווגו זה לזה ונמצא אח נושא את אחותו.
איני והא רב כי איקלע לדרדשיר [מכריז] ואמר מאן הויא ליומא ורב נחמן כי איקלע לשכנציב [מכריז] ואמר מאן הויא ליומא
שאני רבנן דפקיע שמייהו והאמר רבא תבעוה לינשא ונתפייסה צריכה לישב שבעה נקיים רבנן שלוחייהו הוו משדרי ומודעי להו
ואיבעית אימא לרבנן יחודי בעלמא הוא דמייחדי להו דאמר מר אינו דומה מי שיש לו פת בסלו למי שאין לו פת בסלו
The Gemara cites the continuation of the baraita: Furthermore, Rabbi Eliezer ben Ya’akov said that even in marriage, one should be careful not to create a situation that could lead to the birth of mamzerim. Therefore, a man should not marry a woman in this country and then go and marry another woman in a different country, lest a son from one marriage and a daughter from the other, unaware that they are both children of the same father, unite with one another, and it could emerge that a brother marries his sister, the children of whom would be mamzerim.
The Gemara asks: Is that so; is there really such a prohibition? But didn’t Rav, when he happened to come to Dardeshir, make a public announcement saying: Which woman will be my wife for the day, i.e., for the duration of his visit? Since his wife did not accompany him to Dardeshir, he wished to be married to another woman while he was there, in order to avoid a situation that could lead him to having forbidden thoughts. And also Rav Naḥman, when he happened to come to Shakhnetziv, made a public announcement saying: Which woman will be my wife for the day? It would appear, from the fact that both Sages married wives in two different places, that there is no prohibition in doing so.
The Gemara rejects the proof: Sages are different, as their names are renowned, and therefore their children are always identified by their connection to their father. Therefore, Rabbi Eliezer ben Ya’akov’s concern does not apply to them. The Gemara examines Rav and Rav Naḥman’s actions: But didn’t Rava say: With regard to a woman who had an offer of marriage and accepted, the emotional excitement may have caused her to have a flow of menstrual blood, which would making her ritually impure and prohibit her from engaging in intercourse. Even if she was unaware of any flow, she must consider the possibility that it occurred. To purify herself, she needs to wait seven consecutive days that are clean from any flow of menstrual blood and then immerse in a ritual bath. Only then may she marry. If so, how could Rav and Rav Naḥman marry women on the day they arrived?
The Gemara explains: These Sages would send messengers seven days ahead of their arrival and they would inform the women of the Sage’s arrival. In this way, the woman who agreed to marry the Sage would have time to count the seven clean days. And if you wish, say that the Sages’ intentions were merely to be in seclusion [meyaḥadi] with the woman but not to engage in intercourse with her. Therefore, it was permitted to marry her even if she became ritually impure. Being in seclusion with a woman was sufficient to help the Sages avoid any forbidden thoughts, as the Master said: One who has bread in his basket is incomparable to one who does not have bread in his basket, i.e., just as the knowledge that food is readily available is sufficient to psychologically alleviate one’s feelings of hunger, so too, the knowledge that one’s sexual desires could be met lessens the strength of the desire itself.