The Bible speaks of two Israels. One is physical and the other is spiritual.
These two Israels are both in view in Romans 11:25-26.
Right off the bat, in verse 25, we find a warning stating we are not to be ignorant that there is a mystery.
I know this mystery of ignorance cannot refer to physical Israel as being blinded, because time and time again throughout history, they were found to be disobedient and worshiped other gods. Not only have they been blinded by Satan they were also given a delusion by God to believe a lie. I believe the mystery is a reference to 'until the fulness of the Gentiles be come in.'
Many Christians have many interpretations of the phrase 'until the fulness of the Gentiles be come in,' I believe God has in view, 'until the last of the Gentiles that will have become saved has been saved.'
The view of the condition of Israel as being blind will continue until the last of the Gentiles has been saved, which is the last day John 6:39-40, 44, 54.
Even today, physical Israel bears no fruit, in that, they have not turned to Christ, except for a remnant chosen by grace, and this condition of unbelief will continue till the end.
In the Old Testament, when a woman was found to have committed an adultery, by law, she was to be stoned to death. God could not kill physical Israel for adultery (God was a husband to her and she had many lovers) because Jesus had not yet been born.
In order for God to separate Himself from adulterous Israel He had to divorce her (Jer. 3:8) and had to implement Deuteronomy 24:1-4
Verse 4 reads:
Her former husband, which sent her away, may not take her again to be his wife,
after that she is defiled; for that is abomination before the LORD:
So, for those who believe God still has a plan for restoring physical Israel at the end, has not really read or exhausted all the scripture texts pertaining to this subject.
The word “so” in Romans 11:26 means “in this manner.” In what manner? In the manner that all Israel (spiritual Israel, consisting of Jew and Gentile believers) will be saved.
Physical Israel cannot be in view Romans 11:26 because God had divorced and cannot take her back again.