In this age of the Church Christ now lives and acts in and with his Church, in a new way appropriate to this new age. He acts through the sacraments in what the common Tradition of the East and the West calls "the sacramental economy"; this is the communication (or "dispensation") of the fruits of Christ's Paschal mystery in the celebration of the Church's "sacramental" liturgy.
"From the very beginning God blessed all living beings, especially man and woman. The covenant with Noah and with all living things renewed this blessing of fruitfulness despite man's sin which had brought a curse on the ground. But with Abraham, the divine blessing entered into human history which was moving toward death, to redirect it toward life, toward its source. By the faith of "the father of all believers," who embraced the blessing, the history of salvation is inaugurated.
In the Church's liturgy the divine blessing is fully revealed and communicated. The Father is acknowledged and adored as the source and the end of all the blessings of creation and salvation. In his Word who became incarnate, died, and rose for us, he fills us with his blessings. Through his Word, he pours into our hearts the Gift that contains all gifts, the Holy Spirit.
"In the earthly liturgy we share in a foretaste of that heavenly liturgy which is celebrated in the Holy City of Jerusalem toward which we journey as pilgrims, where Christ is sitting at the right hand of God, Minister of the sanctuary and of the true tabernacle. With all the warriors of the heavenly army we sing a hymn of glory to the Lord; venerating the memory of the saints, we hope for some part and fellowship with them; we eagerly await the Savior, our Lord Jesus Christ, until he, our life, shall appear and we too will appear with him in glory."
In this sacramental dispensation of Christ's mystery the Holy Spirit acts in the same way as at other times in the economy of salvation: he prepares the Church to encounter her Lord; he recalls and makes Christ manifest to the faith of the assembly. By his transforming power, he makes the mystery of Christ present here and now. Finally the Spirit of communion unites the Church to the life and mission of Christ.
In the liturgy of the New Covenant every liturgical action, especially the celebration of the Eucharist and the sacraments, is an encounter between Christ and the Church. The liturgical assembly derives its unity from the "communion of the Holy Spirit" who gathers the children of God into the one Body of Christ. This assembly transcends racial, cultural, social—indeed, all human affinities.
Christian liturgy not only recalls the events that saved us but actualizes them, makes them present. The Paschal mystery of Christ is celebrated, not repeated. It is the celebrations that are repeated, and in each celebration there is an outpouring of the Holy Spirit that makes the unique mystery present.
From the Catechism of the Catholic Church Section The Sacramental Economy