Abraham had two sons, Ishmael the eldest and Isaac the younger. Isaac had two sons, Isau the eldest and Jacob the younger.
To understand the conflict and the two stands, we look to the scriptures for knowledge and insight. Israel concerning the gospel and Israel concerning election.
Genesis 25:21-26 Now Isaac pleaded with the Lord for his wife, because she was barren; and the Lord granted his plea, and Rebekah his wife conceived. But the children struggled together whithin her; and she said, "if all is well, why am I like this?" So she went to inquire of the Lord. And the Lord said to her: "Two nations are in your womb, two peoples shall be separated from your body; one people shall be stronger than the other, and the older shall serve the younger." So when her days were fulfilled for her to give birth, indeed there were twins in her womb. And the first came out red. He was like a hairy garment all over; so they called his name Isau. Afterward his brother came out, and his hand took hold of Esau's heel; so his name was called Jacob. Isaac was sixty years old when she bore them.
Genesis 32:27-29 So He said to him, "What is your name?" He said, "Jacob." And He said, "Your name shall no longer be called Jacob, but Israel; for you have struggled with God and with mem, and have prevailed." Then Jacob asked, saying, "Tell me Your name, I pray." And He said, "Why is it that you ask about My name?" And He blessed him there.
Genesis 17:19-21 And God said, Sarah thy wife shall bear a son indeed; and you shall call his name Isaac: and I will establish My covenant with him for an everlasting covenant, and with his seed after him. And as for Ishmael, I have heard you: Behold, I have blessed him, and will make him fruitful, and will multiply him exceedingly; twelve princes shall he beget, and I will make him a great nation. But My covenant will I establish with Isaac, which Sarah shall bear unto you at this set time in the next year.
Romans 9:6-16 But it is not that the word of God has taken no effect. For they are not all Israel who are of Israel, nor are they all children because they are the seed of Abraham; but, "In Isaac your seed shall be called." That is, those who are the children of the flesh, these are not the children of God; but the children of the promise are counted as the seed. For this is the word of promise: "At this time I will come and Sarah shall have a son." And not only this, but when Rebecca also had conceived by one man, even by our father Isaac (for the children not yet being born, nor having done any good or evil, that the purpose of God according to election might stand, not of works but of Him who calls), it was said to her, "The older shall serve the younger." As it is written, "Jacob I have loved, but Isau I have hated." What shall we say then? Is there unrighteousness with God? Certainly not! For He sais to Moses, "I will have mercy on whomever I will have mercy, and I will have compassion on whomever I will have compassion." So then it is not of him who wills, nor of him who runs, but of God who shows mercy.
Romans 11:25-32 For I do not desire, brethren, that you should be ignorant of this mystery, lest you should be wise in your own opinion, that blindness in part has happened to Israel untill the fulness of the Gentiles has come in. And so all Israel will be saved, as it is written: "The Deliverer will come out of Zion; for this is My covenant with them, when I take away their sins." Concerning the gospel they are enemies for your sake, but concerning the election they are beloved for the sake of the fathers. For the gifts and the calling of God are irrevocable. For as you were once disobedient to God, yet have now obtained mercy through their disobedience, even so these also have now been disobedient, that through the mercy shown you they also may obtain mercy. For God has committed them all to disobedience, that He might have mercy on all.