Every liturgical celebration is an action of Christ and of the whole Church. During a celebration of the Mass, or of any liturgy, there are ministers who may seem to be doing the ‘work’. While it is true that some within the community have specific duties to perform, the liturgy is celebrated by all present, according to their proper roles.
The assembly is participating in every moment of the liturgical celebration. We may think of our participation in the Mass as ‘just’ singing the hymns or saying the responses, but we are doing much more than that. First, we offer thanksgiving and sacrifice to God, primarily by joining our prayers to those of the priest, but also by our self-offering through our individual prayers. Second, we unite ourselves to each other through the gestures, responses, and acclamations that belong to the assembly.
When we talk about our Sunday Obligation, we think first of our obligation to God. In accordance with the Third Commandment, the Jewish people kept the Sabbath (Saturday) as a holy day to worship God. After the Resurrection, early Christians began observing Sunday as the Sabbath, a practice which continues until today. Our Sunday obligation is an obligation to celebrate the Eucharist as a sign of our faithfulness to Christ and to His Church.
Since a liturgical celebration is the action of the whole Church, we also have an obligation to each other. The ancient writer Tertullian wrote that every member of the church community has a responsibility to every other member, to support each other in the liturgy through their prayers and their presence. This secondary obligation in no way replaces or reduces our Sunday obligation. Instead it reinforces the need for all of the baptized to continue, as a community, the saving work begun by Jesus.
In the celebration of the Mass, we join ourselves to Jesus in His Paschal Sacrifice. We also come together in unity and community, so that we may become the one Body of Christ, a witness of salvation to the world. As members of the assembly, we accomplish all of this through our full, conscious, and active participation in every liturgical celebration.