Christ's work in the liturgy is sacramental: because his mystery of salvation is made present there by the power of his Holy Spirit; because his Body, which is the Church, is like a sacrament (sign and instrument) in which the Holy Spirit dispenses the mystery of salvation; and because through her liturgical actions the pilgrim Church already participates, as by a foretaste, in the heavenly liturgy.
Source: Catechism of the Catholic Church (Vatican.va)