Romans 9:7-9 Holman Christian Standard Bible (HCSB)

7. Neither are they all children because they are Abraham’s descendants. On the contrary, your offspring will be traced through Isaac.

8. That is, it is not the children by physical descent who are God’s children, but the children of the promise are considered to be the offspring.

9. For this is the statement of the promise: At this time I will come, and Sarah will have a son.

Romans 9