153. Why is the Church the ‘people of God’?
(Comp 153) The Church is the ‘people of God’ because it pleased God to sanctify and save men not in isolation but by making them into one people gathered together by the unity of the Father and the Son and the Holy Spirit.
(CCC 802) Christ Jesus "gave himself for us to redeem us from all iniquity and to purify for himself a people of his own" (Titus 2:14).
To deepen and explain
(CCC 781) "At all times and in every race, anyone who fears God and does what is right has been acceptable to him. He has, however, willed to make men holy and save them, not as individuals without any bond or link between them, but rather to make them into a people who might acknowledge him and serve him in holiness. He therefore chose the Israelite race to be his own people and established a covenant with it. He gradually instructed this people.... All these things, however, happened as a preparation for and figure of that new and perfect covenant which was to be ratified in Christ… The New Covenant in his blood; he called together a race made up of Jews and Gentiles which would be one, not according to the flesh, but in the Spirit" (LG 9; Cf. Acts 10:35; 1 Cor 11:25).
(CCC 803) "You are a chosen race, a royal priesthood, a holy nation, God's own people" (1 Pet 2:9). (CCC 804) One enters into the People of God by faith and Baptism. "All men are called to belong to the new People of God" (LG 13), so that, in Christ, "men may form one family and one People of God" (AG 1).