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.