A miraculous change of substance: why the Real Presence really matters

Catholics believe in the Real Presence of Jesus Christ in the Eucharist. At least, once upon a time, we could assume that this was true. The situation is more complicated today: a 2019 Pew Research study revealed that only 30 percent of Catholics believe this teaching. While this study has problems — namely, its use of the word “actual” to refer to the Church’s eucharistic teaching — it’s clear to this theologian, scholar, and teacher that few people know what the Church teaches relative to the Eucharist.

What is that teaching? The Church teaches that Christ is truly, substantially, or really present in the Eucharist. The God-man who was born in the manger at Bethlehem, who died upon the cross, and ascended into heaven gives Himself to us at every Mass — Body and Blood, Soul and Divinity.

The Church refers to this transformation of bread and wine as transubstantiation. The substance of bread and wine become the Body and Blood of Christ.

But be careful. “Substance” has a particular meaning in the Church. It’s not the “stuff” of the bread and the wine that change. Rather, it is what the bread and wine are at the deepest reality. It’s not what you can see, as St. Thomas Aquinas notes, but what you can’t see. If you look at me, you see hair, a face, a nose, and ears.

But what am I at the level of substance? I am a person. If I have no hair, if my face is disfigured, if my ears fall off, I am still a person.

In the Eucharist, bread and wine cease to exist substantially. What is given now is the person of Jesus Christ, who is made present to us under the signs of bread and wine.

Importantly, we do not eat human beings. We do eat bread and wine. So did the ancient Israelites, who ate unleavened bread, manna from heaven. They understood that the end of men and women would be a banquet with copious wine.

In the New Testament, our Lord fed thousands with miraculous bread. He transformed water into wine. Before He died, He gave Himself under the signs of bread and wine. This is My body. This is My blood. Given up for you.

Thus, in the Eucharist, the signs, appearance, or accidents of bread and wine remain. This is the real miracle of the Eucharist, as Aquinas says. The substance of bread and wine is changed.

This little piece of matter has become Christ. And that too is our destiny. We are to become Christ’s. Totally. Absolutely. He brings us into His heart. Saint Gertrude of Helfta refers to this transformation in her eucharistic visions. As she consumes the Eucharist, she enters the heart of the Lord. The Lord invites her in.

The U.S. Church is engaged in a process of eucharistic revival. Part of this revival is teaching about the true presence of Christ in the Blessed Sacrament. What is given is no mere symbol. It is the very presence of Jesus, given to us.

At the same time, we must recognize that Jesus gives Himself to us in a way that we can receive Him. Signs matter. The Eucharistic elements connect us to the gratuitousness of God as He rescued Egypt from slavery, as He gave manna from heaven, and ultimately as He gave Himself on the night before He died.

And our Lord gave himself so that we can give ourselves. Nothing we have received is ours alone. It is gift. Our lives are to become the presence of the Lord whom we have received.

TIMOTHY P. O’MALLEY is the director of education at the McGrath Institute for Church Life and academic director of the Notre Dame Center for Liturgy. He holds a concurrent appointment in the Department of Theology at the University of Notre Dame. He is the author of several books, including Real Presence: What Does It Mean and Why Does It Matter? (Ave Maria Press, 2021).