7 Nor are all Abraham's descendants the children of God. God said to Abraham, “It is through Isaac that you will have the descendants I promised you.”
8 This means that the children born in the usual way are not the children of God; instead, the children born as a result of God's promise are regarded as the true descendants.
9 For God's promise was made in these words: “At the right time I will come back, and Sarah will have a son.”
10 And this is not all. For Rebecca's two sons had the same father, our ancestor Isaac.
11-12 But in order that the choice of one son might be completely the result of God's own purpose, God said to her, “The elder will serve the younger.” He said this before they were born, before they had done anything either good or bad; so God's choice was based on his call, and not on anything they had done.
13 As the scripture says, “I loved Jacob, but I hated Esau.”
14 Shall we say, then, that God is unjust? Not at all.