In Romans 9:6-8, which is what I referenced, he wasn't just defining who is Israel. He was also defining who is not Israel. He said " For not all who are descended from Israel are Israel". So, he was speaking of two Israels here.
To fully comprehend Romans 9:6-8, it is crucial to analyze it within the larger context of Paul's argument. The concept of "Israel" and its identity cannot be fully grasped unless viewed within its context. It is incorrect to assume that there are two Israels, as there is only one being observed over time, following a promise that God made to the nation.
Paul claims that only his kinsmen are entitled to the "adoption as sons." He then proceeds to explain why and how some of his kinsmen will not receive this promise. In this part of his argument, Paul introduces the idea of God's choice as the reason why some of his kinsmen will not be given the "adoption as sons."
According to Paul, being a member of the "nation of promise" is not determined by one's spirituality, as God can choose to bestow his spirit upon anyone. This means that God's choice of a person does not depend on any pre-existing conditions or attributes they possess.
To coin a phrase from the passage, Paul is talking about "the Israel of promise." Not all of those descended from Jacob will be found among the "Israel of promise" at the time when the promise will be fulfilled.
So, he was clearly talking about an Israel of which those who were part of it were not part of it because of anything physical.
I have a different interpretation. Paul provides two historical examples where God favored one boy over another, both of whom were descendants of Abraham. This suggests that biology may play a role in the decision-making process. In each case, a blood relative of Abraham was chosen over another. These examples illustrate a process of separation within a group of blood relatives, as God had a specific purpose for each boy.
So, with that being said, I'm not sure why you would deny that Paul spoke of an "Israel besides the physical nation of Israel that is entirely spiritual in nature", as I had said.
Not sure what Marks would say, but I should point out that Paul's argument doesn't depend on or even mention spirituality.
It is only those who are the spiritual children of Abraham, of God and of the promise who are counted as being part of the Israel of which all are, all are being and all will be saved.
I also do not agree with this interpretation. In his letter to the Galatians, Paul argues that those who have the same faith as Abraham are considered "sons" in terms of receiving the blessings of Abraham, including the Holy Spirit and eternal life. Paul is making a different point here and acknowledges that the "Adoption as sons" is granted to his relatives by blood. He would not argue against this. Instead, he explains why some of his relatives will not receive this promise.
And would you agree that the basis for being part of true Israel is not anything physical but rather is based on faith?
From my understanding of Paul's argument, being a member of the "Israel of Promise" is determined by God's purpose for each individual. It is not dependent on one's faith or level of spirituality, although these can be indications of God's work in our lives. Paul suggests that God creates individuals with certain attributes, rather than choosing them based on pre-existing ones.
Paul said "there is no difference between Jew and Gentile, so why are you trying to make a difference between them?
Both Jews and Gentiles are indeed justified by faith, without any distinction. However, the subject of Romans 9 is specifically focused on Paul's kinsmen who belong to the same nation as him. In this chapter, Paul is primarily concerned with exploring the differences between those among his people whom God has chosen and those who God has not chosen.