The Church, Jews and Gentiles and their children, is the New Covenant Israel of God.
Ethnic Jews who currently are outside of the Church/the Israel of God, are free to rejoin this club by faith in Christ any time.
Romans 9-11 still indicates that the most of the Jews that have been cut out of the Abrahamic Olive Tree of the CoG, are still in some special providence being dealt with by God's, should be "beloved" to Christians because of the patriarchs, although being enemies because of their opposition to the Gospel, and will be re-ingrafted as a nation.
"Israel" is a much broader concept than under the Old Covenant period. You don't have to become a Jew or ethnic Israelite now in order to be part of Israel or its Commonwealth. Israel is an international nation that is in the process of absorbing all nations and cultures, and whose true covenant members are those that accept Christ as the King of Israel.
The Land of Israel has also expanded in the New Covenant period and is measured from the River (Euphrates) to the ends of the Earth, rather than from the river Euphrates to the Great Sea. ( E.g.Genesis 15:18, Deut 11:24, Ps 72:8, Dan 2:35, Matt 5:5, Rev 11:15)
Therefore remember that at one time you Gentiles in the flesh, called "the uncircumcision" by what is called the circumcision, which is made in the flesh by hands-- remember that you were at that time separated from Christ, alienated from the commonwealth of Israel and strangers to the covenants of promise, having no hope and without God in the world. But now in Christ Jesus you who once were far off have been brought near by the blood of Christ. For he himself is our peace, who has made us both one and has broken down in his flesh the dividing wall of hostility by abolishing the law of commandments expressed in ordinances, that he might create in himself one new man in place of the two, so making peace,
and might reconcile us both to God in one body through the cross, thereby killing the hostility. And he came and preached peace to you who were far off and peace to those who were near. For through him we both have access in one Spirit to the Father. So then you are no longer strangers and aliens, but you are fellow citizens with the saints and members of the household of God, (Ephesians 2:11-19, ESV)
Before Christ came if you wanted full fellowship with God and His people, it wasn't enough to be a Gentile God-fearer like Cornelius, you had to become a Jew by circumcision of you and your sons, and latterly by baptism of the whole family. This was symbolised by the "mid-wall of partition" in the Temple which kept Gentile god-fearers further away from the Holy Place and Holest of All, than Jews. Certain laws also characterised this division, e.g. the food laws.
Now all true Israelites are those who from the heart accept Jesus as King of Israel, and their children are included in the Covenant administration. They do not have to become Jews/ethnic Israelites in order to be part of Israel, but can keep their national and cultural identity along with their spiritual one.
but that was simple and sweet.
