§1363
Sacraments › … › V. The Sacramental Sacrifice Thanksgiving, Memorial, Presence
The sacrificial memorial of Christ and of his Body, the Church
In the sense of Sacred Scripture the memorial is not merely the recollection of past events but the proclamation of the mighty works wrought by God for men. In the liturgical celebration of these events, they become in a certain way present and real. This is how Israel understands its liberation from Egypt: every time Passover is celebrated, the Exodus events are made present to the memory of believers so that they may conform their lives to them.
Source: Catechism of the Catholic Church (Vatican.va)