If you were to put this question to a church scholar, the weight of centuries of writings by popes and councils, saints and church doctors would fall on your head. Happily you’re asking a humble catechist. So let me say the most persuasive argument for me comes by way of Saint Ephrem, a songwriter of 4th-century Syria, who penned a little tune about the Eucharist:
“He called the bread his living body
and he filled it with himself and his Spirit.
He who eats it with faith,
eats Fire and Spirit.”
As we share in the Mass regularly we become “fire-eaters” by Ephrem’s standards. When Jesus said “do this in memory of me,” he didn’t ask to be remembered in a sentimental way. The Eucharist isn’t a locket to wear around our necks. We become what we eat. We participate in the life of Christ, Body and Blood, Spirit and Fire! In a cold, cruel world, why visit the fire now and then when you can become the fire and bring its warmth and light to everyone you meet?
But we don’t become fire-eaters simply by showing up. The Second Vatican Council, in its document the Constitution on the Sacred Liturgy, states the matter with all due urgency: “Mother Church earnestly desires that all the faithful should be led to that fully conscious and active participation in liturgical celebrations which is demanded by the very nature of the liturgy. Such participation by the Christian people as ‘a chosen race, a royal priesthood, a holy nation, a redeemed people’ . . . is their right and duty by reason of their baptism” (no.14). Full, conscious, and active participation involves more than singing, praying responses, and receiving communion. It requires an ever-deepening understanding of the mystery we’re entering. Like any relationship, you don’t get that on the first date or by fading on and off the scene.
Our celebration fosters genuine relationship since “it is Christ who speaks” in the scripture proclaimed at Mass, Pope John Paul reminds us in his apostolic letter Dies Domini (no. 39). In his encyclical letter Ecclesia de Eucharistia he also writes: "The church was born of the Paschal Mystery. For this very reason the Eucharist . . . stands at the centre of the church's life" (no. 3). It also has a cosmic dimension: “Because even when it is celebrated on the humble altar of a country church, the Eucharist is always in some way celebrated on the altar of the world" (no. 8). Don’t miss it.