We believe that Christ changed bread and wine into His own Body and Blood, because:
1. His words clearly say so. At the Last Supper He said: “This is My Body,” not “This is a symbol of My Body,” or “This represents My Body.”
And while they were at supper, Jesus took bread and blessed and broke, and gave it to his disciples, and said, “Take and eat; this is my body.” And taking a cup, he gave thanks and gave it to them, saying, “All of you drink of this; for this is my blood of the new covenant, which is being shed for many unto the forgiveness of sins” (Matthew 26: 26-28).
2. Previously, on the day after the first multiplication of the loaves and fishes, Our Lord had promised to give His Flesh to eat and His Blood to drink. On this occasion, it is clear that the Jews took Our Lord’s words literally. Many of the disciples left Jesus and “walked no more with Him,” because they could not believe such a thing as He promised. But Jesus, although very sad at their leaving, did not take back His words or explain them differently.
” ‘I am the bread of life. Your fathers ate the manna in the desert, and have died. This is the bread that comes down from heaven, so that if anyone eat of it he will not die. I am the living bread that has come down from heaven. If anyone eat of this bread he shall live forever; and the bread that I will give is my flesh for the life of the world.’
“The Jews on that account argued with one another, saying, ‘How can this man give us his flesh to eat?’
“Jesus therefore said to them ‘Amen, amen, I say to you, unless you eat the flesh of the Son of Man, and drink his blood, you shall not have life in you. He who eats my flesh and drinks my blood has life everlasting and I will raise him up on the last day. For my flesh is food indeed, and my blood is drink indeed. He who eats my flesh, and drinks my blood, abides in me and I in him. As the living Father has sent me, and as I live because of the Father, so he who eats me, he also shall live because of me” (John 6:48-57).
3. The Apostles understood that Christ meant His words at the Last Supper to be literal. St. Paul writes:
“The cup of blessing that we bless, is it not the sharing of the blood of Christ? And the bread that we break, is it not the partaking of the body of the Lord? . . . Therefore whoever eats this bread or drinks the cup of the Lord unworthily, will be guilty of the body and the blood of the Lord” (1 Corinthian 10:16; 11:27).
4. It has been the continuous belief of Christians from the beginning of Christianity. St. Augustine said, “Our Lord held Himself in His own hands, when He gave His Body to the disciples.” It was only in the sixteenth century that some Protestants, breaking away from the True Church, denied it and introduced a different doctrine.
The churches which separated in the early centuries from the Catholic Church all believe in the doctrine of the Holy Eucharist as being the very Body and Blood of Christ.