1Abraham took another wife, and her name was Keturah. 2She bore him Zimran, Jokshan, Medan, Midian, Ishbak, and Shuah. 3Jokshan became the father of Sheba, and Dedan. The sons of Dedan were Asshurim, Letushim, and Leummim. 4The sons of Midian were Ephah, Epher, Hanoch, Abida, and Eldaah. All these were the children of Keturah. 5Abraham gave all that he had to Isaac, 6but Abraham gave gifts to the sons of Abraham’s concubines. While he still lived, he sent them away from Isaac his son, eastward, to the east country. 7These are the days of the years of Abraham’s life which he lived: one hundred seventy-five years. 8Abraham gave up his spirit, and died at a good old age, an old man, and full of years, and was gathered to his people. 9Isaac and Ishmael, his sons, buried him in the cave of Machpelah, in the field of Ephron, the son of Zohar the Hittite, which is near Mamre, 10the field which Abraham purchased from the children of Heth. Abraham was buried there with Sarah, his wife. 11After the death of Abraham, God blessed Isaac, his son. Isaac lived by Beer Lahai Roi.
12Now this is the history of the generations of Ishmael, Abraham’s son, whom Hagar the Egyptian, Sarah’s servant, bore to Abraham. 13These are the names of the sons of Ishmael, by their names, according to the order of their birth: the firstborn of Ishmael, Nebaioth, then Kedar, Adbeel, Mibsam, 14Mishma, Dumah, Massa, 15Hadad, Tema, Jetur, Naphish, and Kedemah. 16These are the sons of Ishmael, and these are their names, by their villages, and by their encampments: twelve princes, according to their nations. 17These are the years of the life of Ishmael: one hundred thirty-seven years. He gave up his spirit and died, and was gathered to his people. 18They lived from Havilah to Shur that is before Egypt, as you go toward Assyria. He lived opposite all his relatives.
19This is the history of the generations of Isaac, Abraham’s son. Abraham became the father of Isaac. 20Isaac was forty years old when he took Rebekah, the daughter of Bethuel the Syrian of Paddan Aram, the sister of Laban the Syrian, to be his wife. 21Isaac entreated Yahweh for his wife, because she was barren. Yahweh was entreated by him, and Rebekah his wife conceived. 22The children struggled together within her. She said, “If it is like this, why do I live?” She went to inquire of Yahweh. 23Yahweh said to her,
“Two nations are in your womb.
Two peoples will be separated from your body.
The one people will be stronger than the other people.
The elder will serve the younger.”
24When her days to be delivered were fulfilled, behold, there were twins in her womb. 25The first came out red all over, like a hairy garment. They named him Esau. 26After that, his brother came out, and his hand had hold on Esau’s heel. He was named Jacob. Isaac was sixty years old when she bore them.
27The boys grew. Esau was a skillful hunter, a man of the field. Jacob was a quiet man, living in tents. 28Now Isaac loved Esau, because he ate his venison. Rebekah loved Jacob. 29Jacob boiled stew. Esau came in from the field, and he was famished. 30Esau said to Jacob, “Please feed me with some of that red stew, for I am famished.” Therefore his name was called Edom.
31Jacob said, “First, sell me your birthright.”
32Esau said, “Behold, I am about to die. What good is the birthright to me?”
33Jacob said, “Swear to me first.”
He swore to him. He sold his birthright to Jacob. 34Jacob gave Esau bread and lentil stew. He ate and drank, rose up, and went his way. So Esau despised his birthright.
Isaac was the son of promise to Abraham and Sarah, and the half-brother of Ishmael (who became the father of the Arab people) and the father of Esau (from whom came the Edomites) and Jacob. Isaac was born of a mother beyond childbearing age by a miracle of Yahweh, and was a focus of the testing of Abraham and Sarah, his parents.
The name Isaac means "to laugh, or he laughs," which is based on the response of Sarah to Yahweh's statement to Abraham that she was to bear a son. Sarah was hiding out of sight when this announcement was made by the Angel of Yahweh, and upon hearing this statement, she laughed, which she denied later before the angel. Such an idea was considered impossible but happened as promised by the heavenly visitor. Later, Abraham's faith was tested when God commanded him to sacrifice his only son, Isaac. He followed through with this command of God but received him back alive, since Yahweh kept him from doing so, declaring that now He knew by experience (see the meaning of Hebrew yada') that Abram did not withhold his son.
Later in Isaac's life, he married Rebekah, who bore him Jacob (biography) and Esau (his favorite), and was tricked by Jacob and Rebekah into giving his younger son Jacob his blessing.
Isaac was the only son of Abraham and Sarah, a half-brother of Ishmael and father of Esau and Jacob. Isaac was born when both of his parents were very old, the circumstances surrounding his birth being a test of their faith. The meaning of Isaac's name (“he laughs”) is explained by the fact that Abraham laughed when he was told a son would be born to him at the age of a hundred. Abraham's faith was further tested when he was told to sacrifice Isaac but was stopped at the last moment from carrying out this instruction.
See also Biographies of Bible Characters, People and Characters in the Bible.