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."
Catechism number 1070
In the New Testament the word "liturgy" refers not only to the
celebration of divine worship but also to the proclamation of the Gospel and to
active charity.6 In all of these situations it is a question of the service
of God and neighbor.
In a liturgical celebration the Church is servant in the image of her Lord, the
one "leitourgos";7 she shares in Christ's priesthood
(worship), which is both prophetic (proclamation) and kingly (service of
charity):
The liturgy then is rightly
seen as an exercise of the priestly office of Jesus Christ.
It involves the presentation of man's sanctification under the guise of signs
perceptible by the senses and its accomplishment in ways appropriate to each of
these signs.
In it full public worship is performed by the Mystical Body of Jesus Christ,
that is, by the Head and his members.
From this it follows that every liturgical celebration, because it is an action
of Christ the priest and of his Body which is the Church, is a sacred action
surpassing all others.
No other action of the Church can equal its efficacy by the same title and to
the same degree.8
Liturgy as source of life