Gal. 6:
15For neither is circumcision anything, nor uncircumcision, but a new creation.
16And those who will walk by this rule, peace and mercy
be upon them, and upon the Israel of God.
There is the Israel of the flesh who believe in circumcision, and there is the Israel of God who walk by the rule of Christ. It is natural to understand this as ethnic Israel who followed God, rather than ethnic Israel who believed in circumcision.
There is no text that clearly states that the Church is the Israel of God. They are not all Israel who are of Israel, but that pertains to ethnic Israel. They can be sons of Abraham without being sons of the promise.
But clearly the Church is a royal priesthood, a holy nation, children of the promise by faith in Abraham, united Jew and Gentile under the banner of faith.
I can say this as a strong Dispensationalist, as a strong believer in taking what the Bible says at face value.
There is no more Jew and Gentile after 70ad!
There is no more Jews, called God's Chosen People,
Nor Gentiles; who was Israel's Enemy from Adam to Adam!
There is no more Jew or GreeK!!!!!
And you cannot recreate it no matter how hard you try!
God says in His Word, written by Jewish Apostle's,
in His Kingdom there is no more Jew or Gentile!
Everything concerning your futurist Jew and Gentile is a LIE!
This is your problem and you can twist it how ever you like,
and in the end you must call God a liar to continue in this madness!
Jesus did what Israel could not do; He became Israel, He is Israel!
The Gospel was offered to the Jews first!
Than to the Gentiles in that same generation, 30ad to 70ad!
Then to the rest of the world from 70ad to present.
When God's Word says that all Israel will be saved;
It is speaking of Covenant Israel, not natural Israel!
And this is speaking of anyone in natural Israel, who is in Covenant with God in His Church!
Whether it was, Old Covenant Israel which was the Church, or Light in the wilderness!
(this was the end of Natural Israel as God's Chosen People)
or, New Covenant Israel which is, the Church, or Light set upon a Hill, Mt Zion!
How can you say there is no clear Scripture stating the Church as Covenant Israel!
The whole NEW TESTAMENT (COVENANT), states it ever so clearly!?
What do you do with these New Covenant pages in the Bible?
Use them as toiletry?
After Jesus became the True Israel;
The Gospel of God's Kingdom in Christ Jesus our Lord,
was offered FIRST TO THE JEW, OF THAT EVIL GENERATION,
THEN THE GENTILE.
Thank you! By the very Scripture you posted,
proves in itself, the The Israel of God, was the same as the New Creation!
Who did Paul say was the new Creatures in the New Creation of Christ Jesus?
Or, the Israel of God? The Church!
These things were written and taught in real time!
Before The Old Way in Adam was abolished,
to their kinsmen, in hopes that they might be saved into New Covenant Israel!
Why do you believe there needed to be a new Creation, in the 2nd Adam?
because the Old one in Adam failed!
Do you not understand, that the faithful of Old Covenant Israel,
now abide in New Jerusalem;
in the New Creation, Christ Jesus, the Messiah they looked forward to!
Jesus fulfilled the Law and the Prophets, that this could be so!
There is nothing left to fulfill for them!
These faithful lines of Israel, ended with Jesus on the Cross! 30ad!
And the the Old Way in Adam was ended in 70ad,
when the Holy City, Holy Temple, Holy Institution, was destroyed and made obsolete!
many blessings