Dipping Into the Catechism 159-166

Why is the Church called the temple of the Holy Spirit?
Because the Holy Spirit resides in the body which is the Church, in her Head and in her members. The Holy Spirit also builds up the Church in love by the Word of God, the sacraments, the virtues and charisms.
What are charisms?
Charisms are special gifts of the Holy Spirit which are given to individuals for the good of others, the needs of the world and in particular for the building up of the Church. The discernment of
charisms is the responsibility of the Magisterium. The church: One Holy, catholic and apostolic
Why is the church one?
The Church is one because she has as her source and exemplar the unity of the Trinity of Persons in one God. As her Founder and Head, Jesus Christ re-established the unity of all people in one body. As her soul, the Holy Spirit unites all the faithful in communion with Christ. The Church has but one faith, one sacramental life, one apostolic succession, one common hope, and one and the same charity.
Where does the one church of Christ subsist?
The one Church of Christ, as a society constituted and organised in the world, subsists in the Catholic Church, governed by the successor of Peter and the bishops in communion with him. Only through this Church can one obtain the fullness of the means of salvation since the Lord has entrusted all the blessings of the New Covenant to the apostolic college alone whose head is Peter (The Pope).
How are non-Catholic Christians to be considered?
In the churches and church-like communities which are separated from full communion with the Catholic Church, many elements of sanctification and truth can be found. All of these blessings come from Christ and lead to Catholic unity. Members of these churches and communities are incorporated into Christ by Baptism and so we recognise them as brothers.

How does one commit oneself to work for the unity of Christians?
The desire to restore the unity of all Christians is a gift from Christ and a call of the Spirit. This desire involves the entire Church and it is pursued by conversion of heart, prayer, fraternal knowledge of each other and theological dialogue.
In what way is the church holy?
The Church is holy insofar as the Most Holy God is her author. Christ has given himself for her to sanctify her and make her a source of sanctification. The Holy Spirit gives her life with charity. In the Church one finds the fullness of the means of salvation. Holiness is the vocation of each of her members and the purpose of all her activities. The Church counts among her members the Virgin Mary and numerous Saints who are her models and intercessors. The holiness of the Church is the fountain of sanctification for her children who here on earth recognise themselves as sinners ever in need of conversion and purification.
Why is the Church called catholic?
The Church is catholic, that is universal, insofar as Christ is present in her: “where there is Christ Jesus, there is the Catholic Church” (Saint Ignatius of Antioch). The Church proclaims the fullness and the totality of the faith: she bears and administers the fullness of the means of salvation; she is sent out by Christ on a mission to the whole of the human race.
St Augustine of Hippo said:
“What the soul is to the human body, the Holy Spirit is to the members of Christ,
that is the body of Christ, which is the Church.