Even as Abraham believed God, and it was accounted to him for righteousness.
Know ye therefore that they which are of faith, the same are the children of Abraham.
And the Scripture, foreseeing that God would justify the heathen through faith, preached before the gospel unto Abraham, saying, In thee shall all nations be blessed.
So then they which be of faith are blessed with faithful Abraham.
And if ye be Christ's, then are ye Abraham's seed, and heirs according to the promise.
For we are the circumcision, which worship God in the spirit, and rejoice in Christ Jesus, and have no confidence in the flesh.
But ye are a chosen generation, a royal priesthood, an holy nation, a peculiar people; that ye should shew forth the praises of Him who hath called you out of darkness into His marvelous light.
-I Peter 2:9
Even us, whom He hath called, not of the Jews only, but also of the Gentiles?
As He saith also in Osee, I will call them My people, which were not My people; and her beloved, which was not beloved.
And it shall come to pass, that in the place where it was said unto them, Ye are not My people; there shall they be called the children of the living God.
How do those who believe in a church consisting of only regenerated adults either contradict God's teaching about His church in Scripture, or break the New Testament church from the Old?
New Testaments form one book -one Bible. While we observe a progression of revelation from Genesis to Revelation, the Bible testifies of one purpose -the glory of God; one rule of conduct the law of God; one way of salvation -the gospel of God; and one church -the people of God.
We know from Scripture that the New Testament church is essentially the same as that of the Old Testament for the following reasons:
Both are called God's church. The same word "ekklesia" is used for both the Old and New Testament church (Acts 7:38 and 8:1).
Both are saved by means of the same gospel (Romans 1:1-2; Galatians 3:8).
Both are led by the same King -Jesus Christ (I Timothy 6:15).
The New Testament church is grafted into the same "tree" as the Old Testament church (Romans 11:11-27).
The New Testament church members are called by the same titles as those of the Old Testament, e.g., "children of Abraham" (Galatians 3:6-9, 29), "the circumcision" (Philippians 3:3), and "a royal priesthood" (I Peter 2:9).
Both contain an outward, visible character -the Church Visible -and an inward, spiritual, saving aspect -the Church Invisible (Romans 2:28-29).
The following chart reveals four different forms of administration of God's church and revelation of His covenant within the church. Notice how circumcision and baptism mark the separation between the world and Church Visible. The Holy Spirit's inner application of the sacrament in a person's heart separates the members of the Church Invisible from the Church Visible.