Haven’t posted in a while but this topic intrigued me.
Although many scholars believe the conflict between Isaac and Ishmael can be connected to the Jew/Muslim quarrels of today some Biblical theologist of today, and I will include myself in this too, believe the following story in Genesis to be the basis for what we see today:
Genesis 25:19-34
19 This is the account of Abraham's son Isaac.
Abraham became the father of Isaac,
20 and Isaac was forty years old when he married Rebekah daughter of Bethuel the Aramean from Paddan Aram and sister of Laban the Aramean.
21 Isaac prayed to the LORD on behalf of his wife, because she was barren. The LORD answered his prayer, and his wife Rebekah became pregnant.
22 The babies jostled each other within her, and she said, "Why is this happening to me?" So she went to inquire of the LORD.
23 The LORD said to her,
"Two nations are in your womb,
and two peoples from within you will be separated;
one people will be stronger than the other,
and the older will serve the younger."
24 When the time came for her to give birth, there were twin boys in her womb.
25 The first to come out was red, and his whole body was like a hairy garment; so they named him Esau.
26 After this, his brother came out, with his hand grasping Esau's heel; so he was named Jacob. Isaac was sixty years old when Rebekah gave birth to them.
27 The boys grew up, and Esau became a skillful hunter, a man of the open country, while Jacob was a quiet man, staying among the tents.
28 Isaac, who had a taste for wild game, loved Esau, but Rebekah loved Jacob.
29 Once when Jacob was cooking some stew, Esau came in from the open country, famished.
30 He said to Jacob, "Quick, let me have some of that red stew! I'm famished!" (That is why he was also called Edom.)
31 Jacob replied, "First sell me your birthright."
32 "Look, I am about to die," Esau said. "What good is the birthright to me?"
33 But Jacob said, "Swear to me first." So he swore an oath to him, selling his birthright to Jacob.
34 Then Jacob gave Esau some bread and some lentil stew. He ate and drank, and then got up and left. So Esau despised his birthright.
Though his brother Jacob took advantage of him, the Bible gives Esau little sympathy for his role as victim: he “despised his birthright” (verse 34) by letting his hunger overwhelm his concern for things of lasting value. Because of this he was later labeled “godless”. (Hebrews 12:16)
If you continue to read in Genesis, you’ll see Jacob flatly lied to his father Isaac to receive the birthright. And Jacob spent most of his life in exile for his choices.
But God chose Jacob, even before his born. God’s choice did not depend on how a person behaved. He chose the one he wanted- it was as simple as that.
Is this fair, Paul asked in Romans 9? He concluded that we have no right to find fault with God’s choices, knowing little as we do compared to his infinite understanding.