Question: My Roman Catholic neighbor quotes John 6:53-54 which speaks about eating the flesh and drinking the blood of Jesus Christ in order to have eternal life. What do those verses mean?
Answer: If Jesus were teaching that the literal eating of His flesh and drinking of His blood were necessary for eternal life, it is strange that it is not explained that way anywhere in the Bible. When Jesus preached the Gospel and when the apostles witnessed to the lost, they never spoke about a literal eating and drinking. What they did ask people to do was to "come" to Christ and to "believe" on him for eternal life. When the Philippian jailer asked, "Sirs, what must I do to be saved?" the answer was "Believe on the Lord Jesus Christ, and thou shalt be saved, and thy house" (Acts 16:30-31). If eating the flesh and drinking the blood of Christ were necessary for salvation then this was the wrong answer.
In John 6 Jesus was not teaching about the Lord's Supper and He certainly wasn't advocating cannibalism. Rather, He was teaching about faith. Our Lord had just fed the 5,000, and the multitudes were seeking Him. They were laboring for the food that perishes. Our Lord knew this and therefore gave them instruction about faith (John 6:26-29). When His audience asked about bread our Lord responds and says: "I am the bread of life: he that cometh to me shall never hunger; and he that believeth on me shall never thirst" (John 6:35). Coming to Christ is what it means to eat, and believing is what it means to drink. In verse 40 Jesus promises all who believe on Him will be raised at the last day.
In the centuries following the apostolic era, differing views of the Lord's Supper began to develop. Some of the early writers continued to hold that the elements used in the Supper were purely symbolic. Others, however, began to teach that, in some way, the actual flesh and blood of Christ are combined with the elements.
The doctrine of transubstantiation—that is, the view that the elements actually become the body and blood of Christ who is offered again and again to the Father at the saying of each Mass—was fully defined by Hildebert of Tours in 1134. In 1215 the doctrine was officially adopted by the Roman Church at the Fourth Lateran Council.
In our century, the Second Vatican Council defined the Eucharist in terms of fellowship with Christ and all believers. It also concluded that "no Christian community can be built up unless it has its basis and center in the celebration of the Eucharist." For the Bible-believing Christian, however, that is an honor given only to the teaching and preaching of the Word of God.
Roman Catholic doctrine teaches "an invisible miracle." The bread and the contents of the cup allegedly become the body and blood of Christ, even though such a change is not visible. However, there are no "invisible miracles" in the Bible. When Jesus turned the water into wine at Cana, the water actually became wine. (John 2:1-11)
The Bible does not teach, or even remotely suggest, that Christ must be offered again and again, as is supposedly done in the Mass. The once-for-all death of Christ has infinite merit. It is not repeatable and does not need to be repeated (1 Peter 1:18-20; 1 Peter 3:18; Romans 5:6, 8, 10; Romans 8:32; Ephesians 5:2; Hebrews 9:26-28). Because the substitutionary death of Christ was perfect, it simply needs to be accepted through faith in His blood (Romans 3:25). There can be no compromise on these important doctrinal truths.