The New Covenant in Jesus Christ fulfills the promise of the Old Covenant given to Moses and the People on Mount Sinai. In fulfilling the Old Covenant, Christ perfects the Covenant, making it universal. The scandal of the particularity of God’s love for the children of Abraham becomes the scandal of Universality as God’s love and mercy is lavished upon the whole world. As Saint Paul puts it in Romans 5:8 “But God proves his love for us in that while we were still sinners Christ died for us.”
The Letter to the Hebrews is a magnificent study of the particulars of the Old Covenant and how Christ fulfills them. Christ is the cornerstone of the New Temple, not made by human hands. Christ is the Great High Priest and the Sacrificial Lamb. The pilgrimage to the earthly city of Jerusalem, utterly destroyed by the Romans in 70 AD,  becomes the Christian’s journey to the new and eternal Jerusalem in heaven.
In reflecting on the changes brought about by the New Covenant, I marvel at one of the most significant features of the New Covenant:  moving the Lord’s Day to the first day of the week from the ancient Sabbath of the seventh day. Granted, this transition became easier as more gentiles made up the Christian communities. Still,  in those early decades of the Church, there had to be challenges and obstacles to this revolutionary change. It is a transition largely undocumented in the Scriptures themselves which focus on the conflicts regarding what folks were eating or not eating and the moral witness of Christians in the community and in public. Nevertheless, the Church made the significant transition from the Saturday Sabbath to the Sunday of Resurrection and that must have been quite disruptive in the lives of the faithful, whether gentile or Jew.
However the transition took place, that the primary public display of faith of the Christian was celebrating the Eucharist together on Sunday is undeniable.  Christ did not abolish the Sabbath as a day of rest and worship as celebrated by the people of Israel for well over a thousand years. Indeed, the Resurrection on the first day of the week caused a fundamental shift in how time would be considered holy. The new creation transforms the old creation with healing, forgiveness, and the promise of eternal life. Christians are sanctified in the waters of rebirth and the Eucharist as the Commemoration of the Paschal Mystery is the source and the summit of the Church. The commandment to keep the Sabbath holy is now fulfilled through the celebration of Sunday Mass on the Day of Resurrection and a day of rest and worship markedly different from the other work days of the week.
The celebration of Easter Sunday is an opportunity for all to renew their commitment to keeping the Lord’s Day holy. And let us remember that holiness consists primarily of the things that belong to God. When something is made holy, it is set apart from the ordinary world of this creation to be God’s alone. We celebrate the Resurrection of Jesus Christ from the dead, the unique event in divine and human history. Life has triumphed over death and Jesus is the Risen Lord of All. After the resurrection, the first day of the week took on a sanctity that upended the customs and practices of generations. After the resurrection, there would be no holier time than the Lord’s Day.
How we celebrate Easter Sunday, how we celebrate the Lord’s Day every week—that is the clearest indication that we believe in Jesus Christ, the Son of God, Risen from the Dead. On Easter Sunday we as a community of faith renew our baptismal promises and are refreshed in our Baptismal Grace through the sprinkling rite and the celebration of the Eucharist. The Risen Lord appears among us, Body and Blood, Soul and Divinity. The readings of Easter Sunday and the rest of the Easter Season remind us that the Church is called into Mission immediately upon hearing the news of Christ’s resurrection.  “Go quickly and tell the disciples:  it is the Lord!” We experience paschal joy and want to share that joy with others.
How can we share the Good News of the Resurrection if we aren’t renewed in the source and summit of our faith at the Holy Eucharist? The past years of pandemic have tested our faith. Just as every difficult test probes our strengths and weaknesses, our own commitment to the Lord’s Day is revealed. The obligation to attend Sunday Mass had been suspended for the health and welfare of all. But the obligation to keep the Lord’s Day holy was never suspended. How did we embrace the challenges to communal celebration by being more intentional with our prayer and meditation on the Word of God when we aren’t able to attend Mass? Did we use the suspension of the obligation to attend Mass on Sunday as an excuse to neglect the worship of God in its entirety? And when the obligation to attend Sunday Mass for those whose health allowed was restored, what has been our response? Did we make a firm recommitment to Sunday Mass and keep that promise to God?
We believe in the Resurrection. This is the Mystery of Faith. We share the special knowledge that comes to those who have encountered the Lord and have been sanctified in the sacramental grace of the Church. That special knowledge, the enlightenment of faith, is precious. We have seen the Lord and we want to bring others to him. Our Catholic community has one singular mission and all that we do springs from this mission:  by Word, Sacrament, and Charity proclaim that Jesus Christ has conquered sin and death. 
In the coming weeks of the Easter Season, we will be hearing the Acts of the Apostles. This is the story of how that small group of disciples, having encountered the Risen Lord and having received the Holy Spirit, emerged from their fear and despair and set forth to bring Christ to others. They emerged from the upper room where Christ had gathered them before his death. “Do this in memory of me,” he said. Every time we gather together in our church to celebrate the Eucharist, we hear the Good News of our salvation and join in Christ’s paschal sacrifice. Our church is where Christ himself comes to show us his Resurrected Body, enlightens our minds with the truth, nourishes us with his Body, heals us with his peace, and gives us hope to face the future with confidence. It is at the Sunday Eucharist that our community most perfectly experiences the love of God, which then enables us to love as Christ loves as credible witnesses to the Gospel.