If God's chosen of Israel does not involve His Church under Christ Jesus, then we are all lost. And I guess the early Church must have also forgot to scrap what Apostle Paul said in Ephesians 2, if Israel is no longer important under Christ Jesus...
Eph 2:11-13
11 Wherefore remember, that ye being in time past Gentiles in the flesh, who are called Uncircumcision by that which is called the Circumcision in the flesh made by hands;
12 That at that time ye were without Christ, being aliens from the commonwealth of Israel, and strangers from the covenants of promise, having no hope, and without God in the world:
13 But now in Christ Jesus ye who sometimes were far off are made nigh by the blood of Christ.
(KJV)
What that means, is that any Gentile that believes on Christ Jesus that does not recognize God's concept of His chosen Israel DO NOT inherit those "covenants of promise" moved to Christ's Church. One of the Promises just so happens to involve The Gospel Promise first given through Abraham by Faith (Gal.3).