The Eucharist: Corpus Christi?

The Catholic Church teaches the doctrine of transubstantiation, namely, that in the Eucharist, the communion wafer and the altar wine are transformed and really become the body and blood of Jesus Christ.  Have you ever met anyone who has found this Catholic doctrine to be a bit hard to take?

If so, you shouldn’t be surprised.  When Jesus spoke about eating his flesh and drinking his blood in John 6, his words met with less than an enthusiastic reception.  How can this man give us his flesh to eat? (V 52).  This is a hard saying who can listen to it? (V60).  In fact so many of his disciples abandoned him over this that Jesus had to ask the twelve if they also planned to quit.  It is interesting that Jesus did not run after his disciples saying, Don’t go, I was just speaking metaphorically!

How did the early Church interpret these challenging words of Jesus?  Interesting fact.  One charge the pagan Romans lodged against the Christians was cannibalism.  Why?  You guessed it.  They heard that this sect regularly met to eat and drink human blood.  Did the early Christians say: wait a minute, it’s only a symbol!?  Not at all.  When trying to explain the Eucharist to the Roman Emperor around 155 AD, St. Justin did not mince his words: “For we do not receive these things as common bread or common drink; but as Jesus Christ our Sav­ior being incarnate by God’s word took flesh and blood for our salvation, so also we have been taught that the food consecrated by the word of prayer which comes from him . . . is the flesh and blood of that incarnate Jesus.

Not many Christians questioned the real presence of Christ’s body and blood in the Eucharist till the Middle Ages.  In trying to explain how bread and wine are changed into the body and blood of Christ, several theologians went astray and needed to be corrected by Church authority.  Then St. Thomas Aquinas came along and offered an explanation that became classic.  In all change that we observe in this life, he teaches, appearances change, but deep down, the essence of a thing stays the same.  Example: if, in a fit of mid-life crisis, I traded my mini-van for a Ferrari, abandoned my wife and 5 kids to be beach bum, got tanned, bleached my hair blonde, spiked it, buffed up at the gym, and took a trip to the plastic surgeon, I’d look a lot different on the surface. But for all my trouble, deep down I’d still substantially be the same old baby boomer.

St. Thomas said the Eucharist is the one instance of change we encounter in this world that is exactly the opposite.  The appearances of bread and wine stay the same, but the very essence or substance of these realities, which can’t be detected by a microscope, is totally transformed.  What was once bread and wine are now Christ’s body and blood.   A handy word was coined to describe this unique change.  Transformation of the sub-stance, what stands-under the surface, came to be called transubstantiation.

What makes this happen?  The power of God’s Spirit and Word.  After praying for the Spirit to come (epiklesis), the priest, who stands in the place of Christ, repeats the words of the God-man: This is my Body, This is my Blood.  Sounds to me like Genesis 1: the mighty wind (read Spirit) whips over the surface of the water and God’s Word resounds. Let there be light and there was light.  It is no harder to believe in transubstantiation than to believe in Creation.

But why did Jesus arrange for this transformation of bread and wine?  Because he intended another kind of transformation.  The bread and wine are transformed into the Body and Blood of Christ which are, in turn, meant to transform us.  Ever hear the phrase: you are what you eat? The Lord desires us to be transformed from a motley crew of imperfect individuals into the Body of Christ, come to full stature.

Our evangelical brethren often speak of an intimate, personal relationship with Jesus.  But I ask you, how much more personal and intimate can you get?  We receive the Lord’s body into our physical bodies that we may become him whom we receive!

Such an awesome gift deserves its own feast. And that’s why, back in the days of Thomas Aquinas and St. Francis of Assisi, the Pope decided to institute the Feast of Corpus Christi.

image: Corpus Christi by Fr. Lawrence Lew, O.P. / Flickr (CC BY-NC-ND 2.0). To see more of his images and learn about his ministry, please visit his blog

Marcellino D'Ambrosio, Ph.D.


Dr. Marcellino D’Ambrosio writes from Texas. For info on his resources and pilgrimages to Rome and the Holy Land, visit or call 800.803.0118.

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  • pnyikos

    The problem with Thomas’s solution is that “substance” is an Aristotelian concept and was made at a time when we were ignorant of the atomic structure of matter. Just how are we to reconcile the two? Are we to say that the atoms of bread and wine are miraculously replaced by atoms that were in the physical body of Jesus as he died on the cross? One priest I asked about this said No to this question, but could not explain just how we are to understand it, given what we now know about matter.

  • John

    I would not get hung up on the atomic structure of creation since quantum theory etc. are mathematical models created to emulate scientific observation. While the model is quite valuable to use as a tool to manipulate creation for our own purposes we really don’t know what matter and energy really are. Our models can’t even really explain how an electron can behave as a particle and as a wave at the same time. No unified model that explains how all the forces we observe work. For me, as an engineer with a post graduate degree, it takes more faith to believe that matter is really made up of orbiting sub- atomic particles than it takes to believe one that rose from the dead that the bread and wine are transformed into his body and blood.

  • pnyikos

    Thank you for your comments, John. I know very well that both electrons AND photons (the stuff of light) can behave as waves under some circumstances and also as particles under other circumstances. And I agree, the human mind is incapable of ever grasping even these simple entities.

    But what we do not know is whether our bodies, including Jesus’s earthly body, and the consecrated host, are all made up exclusively of these mysterious entities. So far it appears that the answer is Yes. But if it should ever turn out that “ordinary matter” is only a minority of what makes up the host, etc. and the majority is “dark matter,” then I would rephrase my question accordingly; but it would still be similar to what I wrote originally, and would still ask for a reconciliation with the classic Thomistic idea.

  • John

    Hi Pnyikos,

    What I was trying to say is that quantum mechanics is a mathematical model that describes our scientific observations. The great lie so to speak about science is that we know that the universe is made of these particles. The fact is science doesn’t know that it, only knows that the model (atoms, protons, electrons etc.) behaves with reasonably low error to what we observe. If Physicist says that matter is made of atoms he’s made the leap of faith that the model “is” what matter “is”. The current model is pretty good for predicting atomic fusion and semiconductor behavior and many other earlier models we not good. Still God’s creation exists, it is logical and its behavior can be understood through reason. How it’s truly made I believe is beyond our understanding. Therefore if Jesus says the host becomes his body then we aren’t going to be able to find a tweek to the existing model to explains that. There is nothing observable to model except in a few miraculous events where a host actually became verifiable human flesh.