When Rebekah had been pregnant seven months, she began to wish that the curse of childlessness had not been removed from her. She suffered torturous pain, because her twin sons began their lifelong quarrels in her womb. They strove to kill each other. If Rebekah walked in the vicinity of a temple erected to idols, Esau moved in her body, and if she passed a synagogue or a Bet ha-Midrash, Jacob essayed to break forth from her womb.
The quarrels of the children turned upon such differences as these. Esau would insist that there was no life except the earthly life of material pleasures, and Jacob would reply: "My brother, there are two worlds before us, this world and the world to come. In this world, men eat and drink, and traffic and marry, and bring up sons and daughters, but all this does not take place in the world to come.
If it please thee, do thou take this world, and I will take the other." Esau had Samael as his ally, who desired to slay Jacob in his mother's womb. But the archangel Michael hastened to Jacob's aid. He tried to burn Samael, and the Lord saw it was necessary to constitute a heavenly court for the purpose of arbitrating the case of Michael and Samael.
Even the quarrel between the two brothers regarding the birthright had its beginning before they emerged from the womb of their mother. Each desired to be the first to come into the world. It was only when Esau threatened to carry his point at the expense of his mother's life that Jacob gave way.