Dipping into the Catechism 148-157

What is the origin and the fulfilment of the Church?
The Church finds her origin and fulfilment in the eternal plan of God. She was prepared for in the Old Covenant with the election of Israel, the sign of the future gathering of all the nations. Founded by the words and actions of Jesus Christ, fulfilled by His redeeming death and Resurrection, the Church has been manifested as the mystery of salvation by the outpouring of the Holy Spirit at Pentecost. She will be perfected in the glory of Heaven as the assembly of all the redeemed of the earth.
What is the mission of the Church?
The mission of the Church is to proclaim and establish the Kingdom of God begun by Jesus Christ among all peoples. The Church constitutes on earth the seed and beginning of this salvific Kingdom.
In what way is the Church a mystery?
The Church is a mystery in as much as in her visible reality there is present and active a divine spiritual reality which can only be seen with the eyes of faith.
What does it mean to say that the Church is the universal sacrament of salvation?
This means that she is the sign and instrument both of the reconciliation and communion of all of humanity with God and of the unity of the entire human race.
Why is the Church the ‘people of God’? And what are the characteristics of the people of God?
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. One becomes a member of this people through faith in Christ and Baptism. This people has for its origin God the Father; for its head Jesus Christ; for its hallmark the dignity and freedom of the sons of God; for its law the new commandment of love; for its mission to be the salt of the earth and the light of
the world; and for its destiny the Kingdom of God, already begun on earth.
In what way does the people of God share in the three functions of Christ as Priest, Prophet, and King?
The people of God participate in Christ’s priestly office insofar as the baptized are consecrated by the Holy Spirit to offer spiritual sacrifices. They share in Christ’s prophetic office when with a supernatural sense of faith they adhere unfailingly to that faith and deepen their understanding and witness to it. The people of God share in his kingly office by means of service, imitating Jesus Christ who as King of the universe made himself the servant of all, especially the poor and the suffering.
In what way is the Church the body of Christ?
The risen Christ united His faithful people to Himself in an intimate way by means of the Holy Spirit. In this way, those who believe in Christ, in as much as they are close to Him especially in the Eucharist, are united among themselves in charity. They form one body, the Church, whose unity is experienced in the diversity of its members and its functions.
Who is the Head of this body?
Christ “is the Head of the body, the Church” (Colossians 1:18). The Church lives from Him, in Him and for Him. Christ and the Church make up the “whole Christ” (Saint Augustine); “Head and members form as it were, one and the same mystical person” (Saint Thomas Aquinas).
Why is the Church Called the “Bride of Christ”?
She is called the “Bride of Christ” because the Lord Himself called Himself her “Spouse” (Mark 2:19). The Lord has loved the Church and has joined her to Himself in an everlasting covenant. He has given himself up for her in order to purify her with His blood and “sanctify her” (Eph 5:26), making her the fruitful mother of all the children of God. While the term “body” expresses the unity of the “head” with the members, the term “bride” emphasizes the distinction of the two in their personal relationship.