It is not as though God’s word had failed. For not all who are descended from Israel are Israel.
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.”
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.
For this was how the promise was stated: “At the appointed time I will return, and Sarah will have a son.”
Not only that, but Rebekah’s children were conceived at the same time by our father Isaac.
Yet, before the twins were born or had done anything good or bad—in order that God’s purpose in election might stand:
not by works but by him who calls—she was told, “The older will serve the younger.”
Just as it is written: “Jacob I loved, but Esau I hated.”
What then shall we say? Is God unjust? Not at all!
For he says to Moses, “I will have mercy on whom I have mercy, and I will have compassion on whom I have compassion.”
It does not, therefore, depend on human desire or effort, but on God’s mercy.
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.”
Therefore God has mercy on whom he wants to have mercy, and he hardens whom he wants to harden.
One of you will say to me: “Then why does God still blame us? For who is able to resist his will?”
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?’ ”
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?