The Ekklhsia did not replace Israel. Rather, the New Covenant replaced the Old Covenant when Christ, the Mediator of the New Covenant, shed the Blood of the New Covenant on the cross, thus removing sin, and thus initiating God's New Covenant with the house of Israel, as predicted by Jeremiah. However, only part of the house of Israel accepted this New Covenant by believing in Christ, the Mediator of the New Covenant. This part of the house of Israel is comprised of the saints (believers in Christ). This part of the house of Israel is the Ekklhsia. The Cornerstone of this part of the house of Israel, this Ekklhsia, is Christ, and its citizens are the saints. As Christ says in Matthew 21:42-43, the Stone (Christ) which the builders (the Jews) reject becomes the Cornerstone of the building (Israel), and the kingdom of God is taken from the Jews who do not believe in Him and given to the nation that produces the fruits of the kingdom of God, this nation being this building (Israel), or this part of the building (Israel), whose Cornerstone is Christ and whose citizens are the ones who believe in Him (the saints). The other part of the house of Israel refused this New Covenant by not believing in Christ, the Mediator of the New Covenant. This part of the house of Israel chose to continue to try to reach God in the Old Covenant through the law of Moses. Thus, ever since the cross, the house of Israel has been split into two parts, and thus into two Israels. These two parts of the house of Israel are described in Romans 11:16-24 / 11:25-27, where Paul analogizes Israel in 11:25-27 as the cultivated olive tree in 11:16-24. The very same people who comprise the unbelieving part of the tree in 11:16-24 (the broken-off branches) comprise the unbelieving part of Israel in 11:25-27, and the very same people who comprise the believing part of the tree in 11:16-24 comprise the believing part of Israel in 11:25-27. Thus, the tree in 11:16-24 has to be Israel in 11:25-27; it can't be anything else. Paul says in 11:16-24 / 11:25-27 that part of the tree / Israel does not believe in Christ until Gentile believers join Jewish believers in the part of the tree / Israel that believes in Him, after which the part of the tree / Israel that had not believed in Him will likewise believe in Him and will likewise enter into the part of the tree / Israel that believes in Him, at which point all Israel (both parts) will have been saved by believing in Christ, at which point the transition of the house of Israel from the Old Covenant to the New Covenant will be complete. These two parts of the tree / Israel in 11:16-24 / 11:25-27 are differentiated as the two different Israels in 9:6-8 and in 9:31-32 and 11:7-11. The Israel in 9:6-8 is the part of the tree / Israel that believes in Christ in 11:16-24 / 11:25-27, which is comprised of the saints, both Greek and Jew. As Paul says in 9:6-8, this "Israel" is comprised of "the children of the promise / the children of God," whom he identifies in 4:13-16 (4:16) / 8:14-18 (8:16) as the saints, both Greek and Jew. The Israel in 9:31-32 and 11:7-11 is the part of the tree / Israel that does not believe in Christ in 11:16-24 / 11:25-27, which is comprised of the Jews (non-saints). As Paul says in 9:31-32 and 11:7-11, they stumbled on the Stone of stumbling by not believing in Him, and they did not find what they seek, whereas the election (the Israel in 9:6-8 [the saints, both Greek and Jew]) found it, and the rest (the other of the two groups in view, namely, Israel [the Jews (non-saints)]), were hardened in unbelief, the result being that salvation was given to the Gentiles (the Gentile aspect of the election) in order to make them (Israel [the Jews (non-saints)]) jealous. Paul says that same thing in 11:7-11 that he says in 9:30-32, specifically, that the Gentiles (the Gentile aspect of the election, which is the Israel in 9:6-8, which is the part of the tree / Israel that believes in Christ in 11:16-24 / 11:25-27) have received what Israel (the Israel in 9:31-32 and 11:7-11, which is the part of the tree / Israel that does not believe in Christ in 11:16-24 / 11:25-27) has not received. Paul says that one day, once the fullness (the full number) of the Gentiles has entered into the part of the tree / Israel that believes in Christ in 11:16-24 / 11:25-27, which is the Israel in 9:6-8, which is the children of the promise / the children of God in 4:13-16 / 8:14-18, who are the vessels of mercy in 9:22-24, then the part of the tree / Israel that had not believed in Christ in 11:16-24 / 11:25-27, which is the Israel in 9:31-32 and 11:7-11, who are the vessels of wrath in 9:22-24, will likewise believe in Christ and will likewise enter into the part of the tree / Israel that believes in Christ in 11:16-24 / 11:25-27, at which point all Israel (both parts) will have been saved by believing in Christ, at which point the transition of the house of Israel from the Old Covenant to the New Covenant will be complete. Thus, the Ekklhsia does not replace Israel. Rather, the Old Covenant replaced the New Covenant at the cross, and the Ekklhsia IS the part of the house of Israel that accepts God's New Covenant with the house of Israel by believing in Christ, the Mediator of the New Covenant. The part of the tree / Israel in 11:16-24 / 11:25-27 that does not yet believe in Christ will not be saved separately as broken-off branches. Rather, the unbelieving (Old Covenant) part of the house of Israel will finally believe in Christ, and they, like the believing Gentiles before them, will enter into the part of the house of Israel that believes in Christ (the Ekklhsia) as fellow saints and fellow citizens. Thus, as Paul states, "they" (the Jews [non-saints]) will become "us" (the saints, both Greek and Jew) as fellow citizens of New Covenant Israel, which is the part of the tree / Israel that believes in Christ in Romans 11:16-24 / 11:25-27, which is the Israel in Romans 9:6-8, which is the Israel of God in Galatians 6:15-16, which is the Israel in Ephesians 2:11-13 and 2:19-22, whose Cornerstone is Christ and whose citizens are the saints, both Greek and Jew. The Ekklhsia does not replace Israel. Rather, the New Covenant replaced the Old Covenant at the cross, and the Ekklhsia IS the part of the house of Israel that accepts God's New Covenant with the house of Israel by believing in Christ, the Mediator of the New Covenant; the Ekklhsia IS New Covenant Israel. The Jews who believe in Christ ARE the part of the house of Israel in Romans 11:25-27 that accepts God's New Covenant with the house of Israel by believing in Christ, the Mediator of the New Covenant, and believing Gentiles are now joining these believing Jews as fellow saints and as fellow citizens of New Covenant Israel, which is the part of the house of Israel that accepts the New Covenant in 11:25-27, which is the Israel in 9:6-8, which is why Paul says in Ephesians 2:11-13 that now that the Ephesians believe in Christ, they are no longer excluded from the citizenship of Israel (New Covenant Israel, the part of the house of Israel that accepts God's New Covenant with the house of Israel by believing in Christ, the Mediator of the New Covenant, the Cornerstone of this New Covenant Israel being Christ Himself, and the citizens of this New Covenant Israel being the saints, both Greek and Jew).
Jim