The first followers of Jesus in the "days of His flesh," were not isolated individuals engaged in their private quest for truth. They were Israelites regular members of an established and instituted Community of the "Chosen People" of God ... Indeed; a "Church" already existed when Jesus began His ministry. It was Israel, the People of the Covenant... The existing Covenant was the constant background of His preaching. The Sermon on the Mount was addressed not to an occasional crowd of accidental listeners, but rather to an "inner circle" of those who were already following Jesus . . . "The Little Flock" that the community which Jesus had gathered around Himself was, in fact, the faithful "Remnant" of Israel, a reconstituted People of God. . Each person had to respond individually by an act of personal faith. This personal commitment of faith, however, incorporated the believer into the Community. And this remained forever the pattern of Christian existence: one should believe and confess, and then he is baptized, baptized into the Body. 
- For Matthew, Israel has been replaced by another people, coming from all Gentile peoples: Matt. 8:11-13; 21:43; 27:15-26.
- Paul grants Israel, as the people of God, a general amnesty, as the whole of Israel after a temporary rejection shall be saved at the end of times: Romans 11.
- The Gospel of John shows that throughout the history of Israel there were always two groups among the people; these were separated through the coming of the Messiah-Jesus. Only one of the groups is and has been Israel, and this group is found in the Church.
The term λαικός is etymologically derived from λαός, the semantic significance of which is the idea of the people of God, the pleroma of the church. After all, the Church cannot be theologically conceived in terms of superior and inferior classes, but only as a unity, as one body; nor can it reflect secular structures based on power and divisions, but the inner life of the Holy Trinity, which according to Christian dogmatic tradition, is unity, communion, love and sharing.
In a broken world God calls the whole of humanity to become God's people. For this purpose God chose Israel and then spoke in a unique and decisive way in Jesus Christ, God's Son. Jesus made his own the nature, condition and cause of the whole human race, giving himself as a sacrifice for all. Jesus' life of service, his death and resurrection, are the foundation of a new community, which is built up continually by the good news of the Gospel and the gifts of the sacraments. The Holy Spirit unites in a single body those who follow Jesus Christ and sends them as witnesses into the world. Belonging to the Church means living in communion with God through Jesus Christ in the Holy Spirit.
The famous phrase of St. Augustine can be taken as typical of the whole patristic attitude towards the Old Dispensation. Novum Tesramentum in Vetere latet. Vetus Tesramentum in Novo patet. The New Testament is an accomplishment or a consummation of the Old. Christ Jesus is the Messiah spoken of by the prophets. In Him all promises and expectations are fulfilled. The Law and the Gospel belong together. And nobody can claim to be a true follower of Moses unless he believes that Jesus is the Lord. Any one who does not recognize in Jesus the Messiah, the Anointed of the Lord, does thereby betray the Old Dispensation itself. Only the Church of Christ keeps now the right key to the Scriptures, the true key to the prophecies of old. Because all these prophesies are fulfilled in Christ.
The manifestation of the Kingdom of God is inaugurated in the Church and through the Church, as the historic Body of Christ into which all of the faithful are incorporated as members, and as such constitute the People of God. As members, of the one and same body, the faithful are united with each other and with the divine Head of the Body through divine grace in the new life in Christ. Through this they live the new reality as a continuous communion (κοινωνία) with the Triune God thus becoming "a chosen race, a royal priesthood, a holy nation" (I Pet. 2:9). All of the members of the Church share in the prophetic, high priestly and royal office of Christ. They become through divine grace communicants of all of the blessings of divine glory by their adoption. They live the fullness of the divinely related truth in the Church and obtain the experience of the variety of the gifts of the Holy Spirit in the mystical (sacramental) "μυστηριακή" life of the Church.
We have no right to oppose the Old Testament to the New, or to choose from either that, which appeals to us, and bypass, neglect or reject the rest, through caprice, or following an attempt at rationalizing our choice on the basis of a preconceived ideology. This would be properly heresy (hairesis), and there have been heretics all along the history of revelation. Samaritans read exclusively the Pentateuch, a heresy by ignorance originating in a defective indoctrination. The Karaites professed Biblical purism to the exclusion of rabbinical tradition - from a Jewish standpoint, a formal heresy. St. Paul had denounced the rise of heretical cliques among the Christians of his time.
If the sharpest theological disagreement between Jews and Christians can be faithfully treated and discussed in a humble and respectful manner, thus preserving continuity while working at renewal in relations between the Jewish and Christian communities, it is obvious that the other important areas of our 'roots' can be discussed with less difficulty...
- God's creation of the human person as being in God's image is the place to begin for our understanding of the idea of the term "people of God."
- The history of Israel is the history of the people of God, seen particularly in God's promise to Abraham and the covenant made with Israel on Mount Sinai.
- The creation of the Church by the Incarnate Logos of God established a new relationship with God's people that draw into the covenant all races and all human persons.