Take a look at who Paul said the true Israelites were:
Romans 2:28-29 He is not a Jew, [a member of the Israel of God] who is one outwardly; because of circumcision, which is displayed in the flesh: but he is an Israelite who is circumcision is of the heart, in the Spirit and not in the letter [or outward purported lineage], whose praise is not of men, but of God.
Speaking to the New Covenant church, Colossians 2:11 he said, You are circumcised with the circumcision of Christ.
Christians are now the chosen and blessed Israelites, one people: the nation, from every nation and language, who have faith in God through the Lord Jesus Christ. Matthew 21:43
Paul received his understanding in all this by revelation from God, His secret purpose made known: Ephesians 3:1-6, Galatians 1:12.
Paul says: You, brethren should not be ignorant of this mystery. Romans 11:25
How often have people been asked to pray for the peace of Israel & Jerusalem? How often have you heard the contradiction of Jesus’ offer of universal salvation; that you, even though you are a Christian, are a Gentile and that the ethnic Jew is still the chosen of God? This false teaching is promoted by those who believe in a rapture to heaven of the Church, while ethnic Israel remains to undergo purification on earth. This pretentious idea is not supported by scripture.
Zechariah 12:1-14 describes the scene at the Return of Jesus, where a remnant of Judah will finally find their strength in the Lord and mourn for Him that they pierced.
The New Testament is all about God making a Way for a nation of Spiritual Israelites; Christians that would bring forth fruit consistent with their faithfulness and trust in God. Galatians 5:22-25 A fruitful people of God. Matthew 21:43
Many of the prophets had said that if Judah rejected God and the One He sent to them, she would be pulled up by the roots and so she was: Luke 21:20-24, in 70 AD and will be again in the near future: Jeremiah 12:14, Isaiah 22:14
Jesus is declared to be the new tree of life and “the branches” consist of a newly chosen people, called from every nation, John 15:1-17, to form the Christian Israel of God! Galatians 6:16 Ethnic Israelis are “natural branches” and have been broken off the ‘Olive Tree’, that Jesus is the root and sustainer of. Only be becoming Christian, can they be reattached to the tree of Life.
The Christian church is the circumcision. Circumcision; the Marked and set aside ones, also known as Nazarenes.
Paul said to the gentile church: Brethren: We are the circumcision, which worship God in the Spirit, rejoice in Christ Jesus and have no confidence in the flesh. Philippians 3:3; Colossians 2:11
Ephesians 2:11-18 also contrasts the saved and the unsaved, Christian believers and every other non-Christian person in the world.