Read the Bible.

Paul’s Anguish Over Israel [1] I speak the truth in Christ—I am not lying, my conscience confirms it through the Holy Spirit— [2] I have great sorrow and unceasing anguish in my heart. [3] For I could wish that I myself were cursed and cut off from Christ for the sake of my people, those of my own race, [4] the people of Israel. Theirs is the adoption to sonship; theirs the divine glory, the covenants, the receiving of the law, the temple worship and the promises. [5] Theirs are the patriarchs, and from them is traced the human ancestry of the Messiah, who is God over all, forever praised! Amen. God’s Sovereign Choice [6] It is not as though God’s word had failed. For not all who are descended from Israel are Israel. [7] Nor because they are his descendants are they all Abraham’s children. On the contrary, “It is through Isaac that your offspring will be reckoned.” [8] In other words, it is not the children by physical descent who are God’s children, but it is the children of the promise who are regarded as Abraham’s offspring. [9] For this was how the promise was stated: “At the appointed time I will return, and Sarah will have a son.” [10] Not only that, but Rebekah’s children were conceived at the same time by our father Isaac. [11] Yet, before the twins were born or had done anything good or bad—in order that God’s purpose in election might stand: [12] not by works but by him who calls—she was told, “The older will serve the younger.” [13] Just as it is written: “Jacob I loved, but Esau I hated.” [14] What then shall we say? Is God unjust? Not at all! [15] For he says to Moses, “I will have mercy on whom I have mercy, and I will have compassion on whom I have compassion.” [16] It does not, therefore, depend on human desire or effort, but on God’s mercy. [17] For Scripture says to Pharaoh: “I raised you up for this very purpose, that I might display my power in you and that my name might be proclaimed in all the earth.” [18] Therefore God has mercy on whom he wants to have mercy, and he hardens whom he wants to harden. [19] One of you will say to me: “Then why does God still blame us? For who is able to resist his will?” [20] But who are you, a human being, to talk back to God? “Shall what is formed say to the one who formed it, ‘Why did you make me like this?’ ” [21] Does not the potter have the right to make out of the same lump of clay some pottery for special purposes and some for common use? [22] What if God, although choosing to show his wrath and make his power known, bore with great patience the objects of his wrath—prepared for destruction? [23] What if he did this to make the riches of his glory known to the objects of his mercy, whom he prepared in advance for glory— [24] even us, whom he also called, not only from the Jews but also from the Gentiles? [25] As he says in Hosea: “I will call them ‘my people’ who are not my people; and I will call her ‘my loved one’ who is not my loved one,” [26] and, “In the very place where it was said to them, ‘You are not my people,’ there they will be called ‘children of the living God.’ ” [27] Isaiah cries out concerning Israel: “Though the number of the Israelites be like the sand by the sea, only the remnant will be saved. [28] For the Lord will carry out his sentence on earth with speed and finality.” [29] It is just as Isaiah said previously: “Unless the Lord Almighty had left us descendants, we would have become like Sodom, we would have been like Gomorrah.” Israel’s Unbelief [30] What then shall we say? That the Gentiles, who did not pursue righteousness, have obtained it, a righteousness that is by faith; [31] but the people of Israel, who pursued the law as the way of righteousness, have not attained their goal. [32] Why not? Because they pursued it not by faith but as if it were by works. They stumbled over the stumbling stone. [33] As it is written: “See, I lay in Zion a stone that causes people to stumble and a rock that makes them fall, and the one who believes in him will never be put to shame.”