Romans 9:10

And not only so [Not only is Ishmael rejected for the promised Isaac, but even Isaac's seed, his two sons Esau and Jacob, are made the subject of choice by God, showing that even the seed of the children of promise may be so sifted that part may be received and part rejected, for God indeed did this, accepting Jacob and rejecting Esau]; but Rebecca also having conceived by one, even by our father Isaac [Now, it might be objected by the Jew (unjustly in view of the fact that four of the tribes of Israel were descended from bondwomen) that his case was not parallel to that of Ishmael, for Ishmael was the son of a bondwoman (an Egyptian), and was of a mocking, spiteful disposition (Genesis 21:9). Ishmael's rejection, therefore, was justifiable, while the exclusion of the Jew by Paul's so-called gospel was utterly unwarranted. To this Paul makes answer by citing the cases of Jacob and Esau. They had one father, Isaac the child of promise; and one mother, Rebecca the well beloved, approved of God; they were begotten at one conception, and were twins of one birth, yet God exercised his right to choose between them, and no Jew had ever questioned this, his right of choice. Yea, the unbounded freedom of choice was even more clearly manifest in other details which Paul enumerates]--