It seems that many people today think that Jesus was using a metaphor when He said “Unless you eat the flesh of the Son of Man and drink His blood, you do not have life within you.” They say that eating the flesh and drinking the blood of the Jesus means absorbing his teachings and living by them, rather than literally eating His flesh and drinking His blood. They say that in other verses in Scripture, Jesus refers to Himself as a “gate” and his followers as “sheep,” or Himself as a “vine” and His followers as “branches” without actually meaning these things literally. He also says things like “I am the light of the world” and “you are the salt of the earth” intending “light” and “salt” to be metaphors.
But the discourse in John, Chapter 6, is different. Most of His followers took him literally. They said “How can this man give us his flesh to eat?” They also said “This saying is hard; who can accept it?” They apparently knew that he meant for them to eat his body and drink his blood as a literal action. For that reason, “many of his disciples returned to their former way of life and no longer accompanied him.” There is nothing in this dialogue to indicate that this was a metaphorical teaching. His apostles stuck with him. Peter, for example, said “We have come to know and are convinced that you are the holy one of God.” Then, of course, it became clear at the last supper what exactly he intended when he instituted the sacrament of the Holy Eucharist. I can just hear his twelve apostles saying, perhaps with relief, “Ah, we will eat his flesh and drink under the appearance of bread and wine. Now we understand what a beautiful thing He is doing for us.”
St. Paul reinforces the literality of this when he said, in his first letter to the Corinthians, “Whoever eats the bread or drinks the cup of the Lord unworthily, shall be guilty of the body and blood of the Lord … Whoever eats and drinks without recognizing the body, eats and drinks judgement upon himself.” There can be no doubt that Jesus’ meaning here was literal.
The Eucharist is a sacrament of the Catholic Church and, if you believe that the Catholic Church is the one true Church, then only the Catholic Church can consecrate the bread and wine so that it transubstantiates into the body and blood of Christ. What a beautiful, wonderful gift we have in the Catholic Church. In no other institution can the miracle described in John, Chapter 6, be fully realized. “Whoever eats my flesh and drinks my blood has eternal life, and I will raise him up on the last day.” (John 6:54)