Romans 9:6-9

God’s Sovereign Choice

It is not as though God’s word had failed. For not all who are descended from Israel are Israel. 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.” 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. For this was how the promise was stated: “At the appointed time I will return, and Sarah will have a son.”

Oh I love this one :-).

Save it away for a rainy day :-).

Sure as I'm livin' somebody will argue, "You're not Jewish, your not a descendant of Abraham, so you can't be a child of God."

Really?

"not all who are descended from Israel are Israel."

In Mathew Henry's commentary on something, somewhere he called Israel, "The nation of God." and he meant Jew and Gentile alike I assure you.

"it is the children of the promise who are regarded as Abraham’s offspring"

God's people as it were.

"the children of the promise"