Chapter I-II. Prayer of the Church
Command to Pray
5. Jesus has commanded us to do as he did. On many occasions he said: "Pray," "ask," "seek"  "in my name."  He taught us how to pray in what is known as the Lord's Prayer.  He taught us that prayer is necessary,  that it should be humble,  watchful,  persevering, confident in the Father's goodness,  single-minded, and in conformity with God's nature. 
Here and there in their letters the apostles have handed on to us many prayers, particularly of praise and thanks. They instruct us on prayer in the Holy Spirit,  through Christ,  offered to God,  as to its persistence and constancy,  its power to sanctify,  and on prayer of praise,  thanks,  petition,  and intercession for all. 
Christ's Prayer Continued By The Church
6. Since we are entirely dependent on God, we must acknowledge and express this sovereignty of the Creator, as the devout people of every age have done by means of prayer.
Prayer directed to God must be linked with Christ, the Lord of all, the one Mediator  through whom alone we have access to God. He unites to himself the whole human community  in such a way that there is an intimate bond between the prayer of Christ and the prayer of all humanity. In Christ and in Christ alone human worship of God receives its redemptive value and attains its goal.
7. There is a special and very close bond between Christ and those whom he makes members of his Body, the Church, through the sacrament of rebirth. Thus, from the Head all the riches belonging to the Son flow throughout the whole Body: the communication of the Spirit, the truth, the life, and the participation in the divine sonship that Christ manifested in all his prayer when he dwelt among us.
Christ's priesthood is also shared by the whole Body of the Church, so that the baptized are consecrated as a spiritual temple and holy priesthood through the rebirth of baptism and the anointing by the Holy Spirit  and are empowered to offer the worship of the New Covenant, a worship that derives not from our own powers but from Christ's merit and gift.
"God could give us no greater gift than to establish as our Head the Word through whom he created all things and to unite us to that Head as members. The results are many The Head is Son of God and Son of Man, one as God with the Father and one as man with us. When we speak in prayer to the Father, we do not separate the Son from him and when the Son's Body prays it does not separate itself from its Head. It is the one Savior of his Body, the Lord Christ Jesus, who prays for us and in us and who is prayed to by us. He prays for us as our priest, in us as our Head; he is prayed to by us as our God. Recognize therefore our own voice in him and his voice in us." 
The excellence of Christian prayer lies in its sharing in the reverent love of the only-begotten Son for the Father and in the prayer that the Son put into words in his earthly life and that still continues without ceasing in the name of the whole human race and for its salvation, throughout the universal Church and in all its members.
Action Of The Holy Spirit
8. The unity of the Church at prayer is brought about by the Holy Spirit, who is the same in Christ,  in the whole Church, and in every baptized person. It is this Spirit who "helps us in our weakness" and "intercedes for us with longings too deep for words" (Rom 8:26). As the Spirit of the Son, he gives us "the spirit of adopted children, by which we cry out: Abba, Father" (Rom 8:15; see Gal 4:6; 1 Cor 12:3; Eph 5:18; Jude 20). There can be therefore no Christian prayer without the action of the Holy Spirit, who unites the whole Church and leads it through the Son to the Father.
Community Character Of Prayer
9. It follows that the example and precept of our Lord and the apostles in regard to constant and persevering prayer are not to be seen as a purely legal regulation. They belong to the very essence of the Church itself, which is a community and which in prayer must express its nature as a community. Hence, when the community of believers is first mentioned in the Acts of the Apostles, it is seen as a community gathered together at prayer "with the women and Mary, the mother of Jesus, and his brothers" (Acts 1:14). "There was one heart and soul in the company of those who believed" (Acts 4:32). Their oneness in spirit was founded on the word of God, on the communion of charity, on prayer, and on the eucharist. 
Though prayer in private and in seclusion  is always necessary and to be encouraged  and is practiced by the members of the Church through Christ in the Holy Spirit, there is a special excellence in the prayer of the community. Christ himself has said: "Where two or three are gathered together in my name, I am there in their midst" (Mt 18:20).