>>6614420 (lb)
I'm afraid that the Romans 9:6-8 interpretation is wrong and doesn't prove that there is a "spritual Israel" which is the true Israel.
The literal words are:
And it is not possible that the word of God hath failed; for not all who [are] of Israel are these Israel; nor because they are seed of Abraham [are] all children, but – `in Isaac shall a seed be called to thee;' that is, the children of the flesh – these [are] not children of God; but the children of the promise are reckoned for seed
https://www.biblegateway.com/passage/?search=Romans+9&version=YLT
What this literally says is that not all of Abraham's descendants are Israel - only those that are also descents of Isaac are, because these are the "children of the promise".
This is because Abraham had a son already - Ishmael - before the promise ("mutilate the genitals of thy sons and thy slaves") was made. (Genesis 17:10-14)
Genesis 17:18-22 makes it clear that Isaac is part of this gruesome covenant and Ishmael isn't:
And Abraham saith unto God, O that Ishmael may live before Thee;' and God saith,Sarah thy wife is certainly bearing a son to thee, and thou hast called his name Isaac, and I have established My covenant with him, for a covenant age-during, to his seed after him.
As to Ishmael, I have heard thee; lo, I have blessed him, and made him fruitful, and multiplied him, very exceedingly; twelve princes doth he beget, and I have made him become a great nation; and My covenant I establish with Isaac, whom Sarah doth bear to thee at this appointed time in the next year;' and He finisheth speaking with him, and God goeth up from Abraham.