But the children struggled in her womb — whenever she passed the gate of a pagan temple, Esau moved convulsively to get out; whenever she passed by synagogues and study halls, Jacob moved convulsively to get out. Another explanation: They struggled — Esau said to Jacob, "Let's divide the world." Jacob said to him, "You take this world, and I will take the world to come." And likewise did Esau say to Jacob, "You take the world to come and I will take this world."
Another interpretation: Jacob said to Esau, "Sell me your birthright." He said to him, "I will sell you my birthright." And about this it is stated, "sold that day." (Genesis 25:31) He said to him that he should sell him his birthright on the condition that was made between them that day when they were still in the womb. "And she said, If so, why do I exist?"
Rebecca said: If I had known the pain of childbirth, I would not have prayed for childbirth. Another interpretation: "Why do I exist?" Because in the future there would come twelve tribes from Isaac. Rebecca said: There will be great pain for me, why am I asking that twelve tribes should come from me in this way? Then she went to inquire of Hashem — To the study hall of Shem.