Lumen Gentium

Lumen gentium, the Dogmatic Constitution on the Church, is one of the principal documents of the Second Vatican Council. This dogmatic constitution was promulgated by Pope Paul VI on 21 November 1964, following approval by the assembled bishops by a vote of 2,151 to 5. As is customary with significant Roman Catholic Church documents, it is known by its incipit, "Lumen gentium", Latin for "Light of the Nations".

In its first chapter on ecclesiology, the constitution states that “all the just, from Adam and ‘from Abel, the just one, to the last of the elect,’ will be gathered together with the Father in the universal Church, … a people made one with the unity of the Father, the Son and the Holy Spirit."(2) “Christ made His brothers, called together from all nations, mystically the components of His own Body.”(7) It goes on to describe "the sole Church of Christ which in the Creed is professed as one, holy, catholic and apostolic, which our Saviour, after His Resurrection, commissioned Peter to shepherd, and him and the other apostles to extend and direct with authority, which He erected for all ages as 'the pillar and mainstay of the truth.' This Church, constituted and organized as a society in the present world, subsists in the Catholic Church, which is governed by the successor of Peter and by the bishops in communion with him, although many elements of sanctification and of truth are found outside its visible confines." (8) Only those who "knowing that the Catholic Church was made necessary by Christ, would refuse to enter or to remain in it, could not be saved."(14)

One of the key portions of Lumen gentium is its second chapter, with its declaration that the Church is "the People of God":

At all times and in every race God has given welcome to whosoever fears Him and does what is right. God, however, does not make men holy and save them merely as individuals, without bond or link between one another. Rather has it pleased Him to bring men together as one people, a people which acknowledges Him in truth and serves Him in holiness [...] Christ instituted this new covenant, the new testament, that is to say, in His Blood, calling together a people made up of Jew and gentile, making them one, not according to the flesh but in the Spirit. This was to be the new People of God. For those who believe in Christ, who are reborn not from a perishable but from an imperishable seed through the word of the living God, not from the flesh but from water and the Holy Spirit, are finally established as "a chosen race, a royal priesthood, a holy nation, a purchased people ... who in times past were not a people, but are now the people of God.(9)

...
Wikipedia