When Rivka's pregnancy becomes difficult she asks Hashem why she is suffering. The answer that is given is a little odd (בראשית כה:כג):
וַיֹּאמֶר יְהוָה לָהּ, שְׁנֵי גֹיִים בְּבִטְנֵךְ, וּשְׁנֵי לְאֻמִּים, מִמֵּעַיִךְ יִפָּרֵדוּ
And Hashem said to her: 'Two nations are in your womb; and two regimes from your insides shall be separated ...'
What was Rivka's concern and how does this answer alleviate that concern? A famous midrash informs us that the baby would get agitated whenever she passed by a beit midrash and also whenever she passed by a house of idol worship. She was worried about the nature of her child. The difficulty with this explanation is the answer that she is given. How does the fact that instead of one child there are two bring her any peace? All that she finds out is that she had one bad apple in her womb.
What obfuscates things further is another midrash that does not seem to fit at all. Rashi brings the gemara (ע"ז יא ע"ב):
גיים כתיב, אלו אנטונינוס ורבי שלא פסקו מעל שולחנם לא צנון ולא חזרת לא בימות החמה ולא בימות הגשמים
It is spelled גֵיִים, 'proud ones.' These are Antoninus and Rabbi - for neither radish nor horseradish ceased [to be found] on their tables neither during the sunny season nor during the rainy season.
What in the world does that have to do with Rivka's concern? The Maharal has a brilliant explanation in Gur Aryeh. He explains that Rivka's natural concern after hearing that she was having twins was that history was repeating itself. She remembered the behavior of Ishmael all too well and was deeply concerned that she was bringing another "Pereh Adam", a wild beast of a man, into the world. The midrash explains that she was informed that she was having two גֵיִים, proud men. Edom might be a rasha but he will be a human rasha and not a barbarian. An appreciation for that which separates man from animal (eating at designated place, appreciating delicacies such as radish) is a level of moral sensitivity in and of itself and thus curtails some of the baser behavior men can exhibit even in a person with low moral character. Thus there will be a common bond of humanity between Edom and Israel that is not shared with Ishmael.
