In Context

4 the people of Israel. Theirs is the adoption as sons; theirs the divine glory, the covenants, the receiving of the law, the temple worship and the promises.

5 Theirs are the patriarchs, and from them is traced the human ancestry of Christ, who is God over all, forever praised! Amen.

6 It is not as though God's word had failed. For not all who are descended from Israel are Israel.

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 natural children 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."

Romans 9:7 in Other Translations