Catechism of the Catholic Church

1066 In the Symbol of the faith the Church confesses the mystery of the Holy Trinity and of the plan of God's "good pleasure" for all creation: the Father accomplishes the "mystery of his will" by giving his beloved Son and his Holy Spirit for the salvation of the world and for the glory of his name. ¹ Such is the mystery of Christ, revealed and fulfilled in history according to the wisely ordered plan that St. Paul calls the "plan of the mystery" ² and the patristic tradition will call the "economy of the Word incarnate" or the "economy of salvation."

1067 "The wonderful works of God among the people of the Old Testament were but a prelude to the work of Christ the Lord in redeeming mankind and giving perfect glory to God. He accomplished this work principally by the Paschal mystery of his blessed Passion, Resurrection from the dead, and glorious Ascension, whereby 'dying he destroyed our death, rising he restored our life.' For it was from the side of Christ as he slept the sleep of death upon the cross that there came forth 'the wondrous sacrament of the whole Church."' ³ For this reason, the Church celebrates in the liturgy above all the Paschal mystery by which Christ accomplished the work of our salvation.

1068 It is this mystery of Christ that the Church proclaims and celebrates in her liturgy so that the faithful may live from it and bear witness to it in the world:

For it is in the liturgy, especially in the divine sacrifice of the Eucharist, that "the work of our redemption is accomplished," and it is through the liturgy especially that the faithful are enabled to express in their lives and manifest to others the mystery of Christ and the real nature of the true Church. ⁴