Catechism of the Catholic Church
1084 "Seated at the right hand of the Father" and pouring out the Holy Spirit on his Body which is the Church, Christ now acts through the sacraments he instituted to communicate his grace. The sacraments are perceptible signs (words and actions) accessible to our human nature. By the action of Christ and the power of the Holy Spirit they make present efficaciously the grace that they signify.
1085 In the liturgy of the Church, it is principally his own Paschal mystery that Christ signifies and makes present. During his earthly life Jesus announced his Paschal mystery by his teaching and anticipated it by his actions. When his Hour comes, he lives out the unique event of history which does not pass away: Jesus dies, is buried, rises from the dead, and is seated at the right hand of the Father "once for all." 8 His Paschal mystery is a real event that occurred in our history, but it is unique: all other historical events happen once, and then they pass away, swallowed up in the past. The Paschal mystery of Christ, by contrast, cannot remain only in the past, because by his death he destroyed death, and all that Christ is - all that he did and suffered for all men - participates in the divine eternity, and so transcends all times while being made present in them all. The event of the Cross and Resurrection abides and draws everything toward life.
English Translation of the Cathechism of the Catholic Church for the United States of America © 1997, United States Catholic Conference, Inc.