I apologize for the length of some of these posts, I need to consider breaking them into 2 days possibly.
The common accusation against postmillennial and amillennial eschatology is that it affirms "replacement theology". Whenever you read defenses of premillennialism it is inevitable that the 'replacement theology' accusation will arise, every single time. Essentially, if you do not want to follow the links, replacement theology affirms that the New Testament Church replaces Israel. The point of contention is whether or not modern day Israel is still the covenant people of God along with the Church also being the covenant people of God. Replacement theology, asserts that there is one covenant people and it's not Israel. it's the church. The premillennialist typically holds some sort of Dual covenant theology where they believe that ethnic Israel is still the covenant people of God, as well as the Church, and eventually they will be brought together, and Israel will come to see Christ as their redeemer... when the time is right, but not right now.
Let me say first that I completely disagree with the idea of a dual covenant, there is one name by which people are saved and that is the Lord Jesus Christ. Christ is the fulfillment of the Law and the Prophets, and his people, the church, indeed are the 'true Israel' the real children of Abraham. So to say that 'national' or 'ethnic' Israel are the chosen, as well as the church, is something I disagree with, and scriptural support abounds for this disagreement. On the other hand I vehemently disagree with 'replacement theology' as well. The Church has not replaced Israel as the 'true Israel', the Church simply IS the true Israel. Moreover Israel was the church before the incarnation. The Church was born long before Pentecost, the church began when a promise was made that the seed of the woman would crush the serpent in Genesis.
A proper understanding of all scripture centers on Christ as the beginning, as well as the consummation of all things. In the old testament the believers of Israel and her proselytes (gentile believers) were his people. In the new testament the believers of Israel and her proselytes (gentile believers) are his people. There has been no change! The only difference is that much of ethnic Israel rejected her messiah and much of the gentile world were grafted in by that same Messiah.
Just think of how Israel was created... Promise to Abraham... Delivered from Egypt by blood of passover lamb... delivered through water (Red Sea / Jordan River)... Redeemed by grace even though Law was constantly violated. The means of deliverance and salvation through the water and the blood, is the same means of deliverance in Christ, and Christ is the embodiment of those events. Jesus is the bread of heaven... the same as the manna which sustained Israel. Every old testament redemption finds its fulfillment in Christ, it was Christ in the passover, it was his baptism in the red sea, it was his body that sustained them as manna in the wilderness. Israel was delivered, redeemed, and sustained by Christ. The church is delivered, redeemed, and sustained by Christ. The point is that True Israel and the Church are one body and the Church and True Israel are one body. Replacement theology assumes a change that has not happened. Ethnic Israel has always had unbelievers in her midst that stood condemned, and always had a remnant that was the 'true Israel' by faith. I am not sure how people miss this.
Now, because there has always been one church, one true Israel, and because they are one and the same institution, we would have to say that the Dual Covenant people practice replacement theology in reverse. Looking backward on history they replace the church with Israel! They should see Israel as the old testament church, instead they replaced the church with ethnic Israel, and are left trying to put everything together with some dual covenant nonsense.
Is this even important? YES! The point, church, is that Israel's story is your story! The call to "remember when the Lord brought you out of Egypt" is a call to you. It is your history, it is your family, it is your promises. Moreover when thinking back to old testament church, the promises that we have seen fulfilled in Christ are their promises, their redemption, their grace. We are one! Our separation is that we exist chronologically after Christ, and they existed before him, but remember he is not only omega, but alpha as well. We have had the fortune of seeing the things they longed for.