Friends, today’s Gospel focuses on the spiritual power of the Eucharist. A central claim of the Catholic Church is that Jesus is substantially present under the forms of bread and wine. His presence is not simply evocative and symbolic, but rather real, true, and substantial.
To verify this scripturally, look at the accounts of the Last Supper in Matthew, Mark, and Luke—and also in Paul. But look especially at the sixth chapter of John’s Gospel. Jesus says, “Unless you eat the flesh of the Son of Man and drink his blood, you do not have life within you.” And when they object, Jesus does not soften his language; he intensifies it.
This is the ground for the Church’s defense of the Real Presence. How can we make sense of it? It has everything to do with who Jesus is. If he were simply an ordinary human being, his words would have, at best, a symbolic resonance. But Jesus is God, and what God says, is.
Thus, when Jesus’ words over the bread and wine are spoken, they change into what the words signify. They become really, truly, and substantially the Body and Blood of the Lord.