The command to Remember the sabbath day—keep it holy comes to us from God’s 10 Commandments to Moses (Ex 20:8-11). We have a moral obligation to honor the Lord’s Day, moved from Saturday in the Old Testament to Sunday by virtue of Jesus’s Resurrection from the dead on this day, which no law can invalidate.
Christians are obliged to set Sunday apart for worship of God and as a day unlike others. The most salutary way we do this is by participating at Sunday Mass.
Therefore, the Sacred Liturgy, and particularly the Holy Eucharist, is the very heart and foundation of our Catholic faith. It is during the Holy Sacrifice of the Mass that the saving death and resurrection of Jesus are made present to us, our covenant with Our Lord is renewed, and God, in the person of Jesus Christ, comes to us and makes himself truly present for us in his Body, Blood, Soul and Divinity. It is an irreplaceable gift; a foretaste of Heaven itself.
We know the challenges of the Christian life are great and we need nourishment and community to successfully “run the race” (2Tim. 4:7). Gathering at Mass on Sunday to hear God’s word and to offer our lives as spiritual worship (Rom 12:1) along with the Body and Blood of the Lord present on the altar are indispensable tools God gives us for our salvation.