“And not onely this, but when Rebecca also had conceiued by one, euen by our father Isaac,”
1611 King James Version (KJV)
9:10 And that God's blessing does not belong to all the descendants of Abraham, appears not only by this instance, but by that of Esau and Jacob, who was chosen to inherit the blessing, before either of them had done good or evil. The apostle mentions this to show, that neither were their ancestors accepted through any merit of their own. That the purpose of God according to election might stand - Whose purpose was, to elect or choose the promised seed. Not of works - Not for any preceding merit in him he chose. But of him that called - Of his own good pleasure who called to that privilege whom he saw good.
Ro 9:10 And not only [this]. The first argument is that the true seed are children of the promise, a spiritual seed rather than of the flesh. But when Rebecca also had conceived, etc. The second argument, now begun, is that God has the right to reject what nation he will, including the Jews, and to choose other races if he will. This is shown by facts from history. He did exercise the right of choice when he chose Jacob as the chosen nation, instead of Esau. The facts are recited to show this.