Genesis 25:19-26:5
This is the story of Isaac, son of Abraham. Abraham begot Isaac. Isaac was forty years old when he took to wife Rebekah, daughter of Bethuel the Aramean of Paddan-aram, sister of Laban the Aramean. Isaac pleaded with the Lord on behalf of his wife, because she was barren; and the Lord responded to his plea, and his wife Rebekah conceived. But the children struggled in her womb, and she said, "If so, why do I exist?" She went to inquire of the Lord, and the Lord answered her,
"Two nations are in your womb,
Two separate peoples shall issue from your body;
One people shall be mightier than the other,
And the older shall serve the younger."
When her time to give birth was at hand, there were twins in her womb. The first one emerged red, like a hairy mantle all over; so they named him Esau. Then his brother emerged, holding on to the heel of Esau; so they named him Jacob. Isaac was sixty years old when they were born.
When the boys grew up, Esau became a skillful hunter, a man of the outdoors; but Jacob was a mild man who stayed in camp. Isaac favored Esau because he had a taste for game; but Rebekah favored Jacob. Once when Jacob was cooking a stew, Esau came in from the open, famished. And Esau said to Jacob, "Give me some of that red stuff to gulp down, for I am famished"—which is why he was named Edom. Jacob said, "First sell me your birthright." And Esau said, "I am at the point of death, so of what use is my birthright to me?" But Jacob said, "Swear to me first." So he swore to him, and sold his birthright to Jacob. Jacob then gave Esau bread and lentil stew; he ate and drank, and he rose and went away. Thus did Esau spurn the birthright.
There was a famine in the land—aside from the previous famine that had occurred in the days of Abraham—and Isaac went to Abimelech, king of the Philistines, in Gerar. The Lord had appeared to him and said, "Do not go down to Egypt; stay in the land which I point out to you. Reside in this land, and I will be with you and bless you; I will assign all these lands to you and to your heirs, fulfilling the oath that I swore to your father Abraham. I will make your heirs as numerous as the stars of heaven, and assign to your heirs all these lands, so that all the nations of the earth shall bless themselves by your heirs--inasmuch as Abraham obeyed Me and kept My charge: My commandments, My laws, and My teachings."