The children were pushing against one another within her, so she said, "If so, why am I?" and she went to seek Hashem. Hashem said to her, "Two nations are in your womb, and two peoples from your insides will be divided. One nation will overpower the other, and the older will serve the younger."
The Ohr Hachaim asks what the exact meaning of the word ויתרוצצו is.
He also inquires what Rivkah was saying with her question, “If so, what am I?” It seems that her intention was that the pain of pregnancy caused her to regret wanting to have children in the first place. This is untenable; a Tzadeikes like Rivka would not refuse to bring children into the world due to some short-term pain during pregnancy. Additionally, this explanation does not account for the answer she received from Hashem. How was she appeased by the fact that there were two conflicting nations in her womb? How is the pain more bearable now?
The Ohr Hachaim explains that the word ויתרצצו is based on the word ריצוץ, which means to crush. The children were crushing each other, or so she felt, and she was sure neither would be born alive. It felt like they were going to be crushed to death, rendering the pregnancy pointless. No baby would emerge from it anyway.
She went to seek Hashem, which means she davened to Hashem that her pregnancy be saved and that her baby not be lost. She also went to find out from Hashem what the meaning of this was. Hashem would not perform a miracle for no purpose and if she got pregnant after so many years, there must be a purpose to it.
The answer she received was that she was having twins and a unique set of twins. Usually, twins are the closest of friends, after they have spent nine months in close proximity and friendship. These twins were different. Each one was to be considered a nation on its own, not a twin of the other.
Not only that, but each one is a king on its own, with its own nation, and they do not belong together. They are pushing against each other, fighting over the space. Even before they are born, they are different and do not belong in the same space. This is why the Torah writes ממעיך יפרדו – from your womb they will be separated. From the womb and on, they will always be different, in constant conflict.
This is the reason Rivkah’s pregnancy experience was so different from others’ and she felt a crushing sensation. It is the two fetuses pushing against each other.
The possuk then writes that one nation will overpower the other. Each nation, from the time of its founders' fetal state, is constantly attempting to overpower the other. This is why they were fighting inside there and crushing each other. Each one wishes to ensure the other stays down that he can elevate himself. As the Gemara writes, ‘Tzur was only filled up with the destruction of Yerushalayim’.
The end of the possuk that tells us ורב יעבוד צעיר – the older one will serve the younger one, is another point in their conflict. Not only does one have to be above the other, but the loser has to be subservient to the winner. If Yaakov wins, Esav is his slave, and vice versa. Each twin is not only attempting to win the top spot, but he is also trying to subjugate the other one to his will.
Chazal tell us that a human and a snake cannot live in the same area. Each of the brothers is like a snake to the other, attempting to subjugate the other.
This is not how regular twins act, and the pregnancy was appropriately different from all others.
