1. John taught us that ALL humans who do not believe in the Son of God are anti-Christ(ian). (1 John 2:22-23).
2. Paul taught that not ALL naturally-born descendants of Abraham, Isaac and Jacob are Israel (Romans 9:6-8), because those of the naturally-born descendants of Abraham, Isaac and Jacob who do not believe in the seed of Abraham (Christ) are broken off from God's covenant-promises that He made with Abraham and his seed (Romans 11:1-5, 17).
They are broken off from the Israel of God. (Galatians 6:16).
3. Jeremiah said that God would not cut off
ALL the seed of Israel when God brings in a New Covenant (Jeremiah 31:36-37), meaning that a remnant would be saved - just as occurred when Jesus had died and risen again (as Paul stated in Romans 11:1-5).
4. Paul taught us that Gentiles who do believe are grafted into Israel - into God's covenant-promises with Abraham and his seed - and are among the remnant
of the naturally-born descendants of Abraham, Isaac and Jacob who believe. (Romans 11:17).
5. Peter and Paul both taught us that together these Jews and Gentiles in Christ are the living stones that are God's Tabernacle, indwelt by the Holy Spirit. (Ephesians 2:19-22; 1 Peter 2:5).
6. Paul taught that in Christ there is neither Jew nor Gentile. (Galatians 3:28).
7. Therefore simple arithmetic and logic tells us that the church = Israel = the church.
The person who coined the phrase "Replacement Theology" in respect of what Jesus and His apostles taught is very, very confused, does not understand basic arithmetic, and exalts one anti-Christ(ian) nation above all other anti-Christ(ian) people merely because the nation that he exalts above all other unbelievers, are naturally-born descendants of Abraham, Isaac and Jacob.
Those who follow this heresy are so confused that they do not even realize that they are practicing replacement theology by replacing Christ - the seed who inherits all the promises of God contained in God's covenant with Abraham and his seed - with people who reject Him.
They also fail to realize that the Deliverer who came out of Zion is Jesus, and the day in which He made a covenant (the new covenant) with Israel was the day He took away their (and our) sins (Romans 11:26-27).
They do not understand that ever since the Deliverer came out of Zion and made a new covenant with Israel in the day He took away their (and our sins):-
(a) The fullness of the Gentiles is being grafted into Israel through faith in Christ, sharing with the naturally-born believing descendants of Israel in the root and fatness of the Olive tree; and
(b) IF (Romans 11:23) an unbelieving Jewish person repents of his or her unbelief, the person will be grafted back into the Israel that he is a naturally born descendant of ("their own Olive tree") - and this is because:
i. For the sake of God's promise to Abraham, Isaac and Jacob, they are still loved.
ii. God had mercy on Gentiles who believe through their unbelief.
iii. God is able to graft them in again.
Those who follow this heresy of replacing Israel in Christ with those who are not in Christ, calling them "the chosen nation, or "the elect of God" are so confused that they think the Deliverer is still going to come out of Zion in order to take away ungodliness from Jacob by taking away their sins, and making a new covenant with Jacob (the house of Israel and the house of Judah) in His blood.
They do not understand that when Jesus returns, He returns in judgment of unbelievers, He is not going to return as the Deliverer who takes away sin a second time.
Total misconception of the testimony of Apostle Paul in context from Romans chapter 9 to chapter 11. He expresses as like going through 'birth pangs', when he reflects about his 'kinsmen', the descendant of Jacob/Israel, Israelites. Ones, who are hostile and heart-harden to the saving power of the Gospel, and are not saved.
In Romans chapter 11, he starts of by witnessing to the Gentile church, 'has GOD rejected HIS people?' And. verse 2, he continues, 'GOD has not rejected HIS people whom HE foreknew.'
Verse 11, 'So I ask, did they stumble in order that they might fail? By no means! Rather, through their trespass salvation has come to the Gentiles, .......' Verse 16, 'If the dough offered as firstfruits is holy, so is the whole lump, and if the root is holy, so are the branches.'
Next verses, he uses the parables about a 'cultivated olive tree and branches', that is the true descendants of Jacob/Israel. And, 'cut wild olive tree branches', that are the Gentiles. To some of the branches of Israel have been cut off, and branches of the Gentiles have been grafted in.
But, down the line, he also warns Gentile believers, as grafted branches, that they can be cut off too due to unfruitfullness. And, GOD is able to graft back again the initial olive tree branches HE have cut before, back into their places. (Verse 17-24)
Verse 25-32, He concludes, also cautioning the Gentile believers to mindful of the reason and purpose of GOD, why the remaining Israel rejected the Gospel. The mystery he reveals,
'a partial hardening has come upon Israel, until the fullness of the Gentiles has come in. And in this way all Israel will be saved, .....'
'As regards the Gospel, they are enemies for your sake. But as regards election, they are beloved for the sake of their forefathers. For the gifts and calling of GOD are irrevocable.'
'For just as you were at one time disobedient to GOD but now have received mercy because of their disobedience, so they too have now been disobedient in order that by the mercy shown to you they also may now receive mercy. For GOD has consigned all to disobedience. that HE may have mercy on all.'
- all Israel will be saved - meaning, all the descendants of Jacob/Israel will be saved in the end.
Furthermore, points to ponder on - Why GOD have to send the two witnesses back to Israel when HE have rejected them, during the reign of anti-CHRIST?
And, during Armageddon, when the forces of the world joined together to completely destroy Israel for their good. Therefore, why Jesus have to descend with His angels from Heaven to defend Israel on that day? Even to the point to disintegrate the very enemy forces bodies from where they stand?