In John 6:53-56 we find a strange statement by Jesus that troubled even His disciples (6:60):
53 So Jesus said to them, “Truly, truly, I say to you, unless you eat the flesh of the Son of Man and drink His blood, you have no life in yourselves.
54 “He who eats My flesh and drinks My blood has eternal life, and I will raise him up on the last day.
55 “For My flesh is true food, and My blood is true drink.
56 “He who eats My flesh and drinks My blood abides in Me, and I in him.
At first glance, Jesus’s words appear to advocate a kind of cannibalism, and at least one group have taken His words to mean that during contemporary instances of the Lord’s Supper the bread and wine actually become His flesh and blood (the doctrine of transubstantiation). So, how should we understand Jesus’s saying?
First, we have to remember that our hermeneutic (interpretive method) needs to be consistent. We don’t use one hermeneutic for easy passages and another for difficult ones. So we stick with the literal grammatical historical method – the normal way we would read any document – and see what we come up with.
One key principle to consider is that unless there is clear contextual evidence that a figure of speech is being employed, we should assume that the words mean exactly what they say (in this case, that we should literally eat and drink His flesh and blood).
Another important principle in view here is the progress of revelation: earlier passages set definitions for later passages. In other words, we read later passages in light of the information revealed in earlier passages.
The contextual key to understanding what Jesus means is found in 6:54 – the one who eats and drinks has eternal life. Now, Jesus had earlier identified only one condition for eternal life. In John 3:15-16, He told Nicodemus that the only condition for eternal life was belief in Him. If Jesus left out other important conditions, then His statement in 3:15-16 would not be true.
Immediately preceding Jesus’s statement in 6:53-56, Jesus reiterates that the only condition for eternal life is belief in Him (6:40, 47). Further, in the immediate context, Jesus has just created bread for the people, providing an object lesson for the truth that He Himself is the bread of life (6:35,48). When the people ask Him what they should do, He answers that they should believe in Him (6:29). They understood that by His object lesson He was connecting Himself to the manna that came from heaven, by which Israel had long ago been sustained (6:30-31). Jesus explains that manna provided a temporary sustenance but the true bread from heaven provides life for all (6:32-33). Their response: “Give us this bread!” (6:34). Jesus then explains that He is the bread of life (6:35). His listeners would understand (in light of the context) that He was not claiming to be a baked product, but that He was God’s true provision of life, and He came from heaven. They understood what He was saying, initially.
At first they only grumbled because He claimed to be from heaven, not because He claimed to be bread – they understood He was using a figure of speech by the connection to the manna of old (6:41-42). He again emphasizes the one condition for eternal life (6:47), and restates that He is, indeed, the bread of life (6:47-48). In 6:48-50 Jesus contrasts Himself with the manna in the wilderness: what the manna could not do (sustain life permanently), He does. At this point, some of His listeners now begin to argue about the meaning of His “flesh-eating” statement (6:52). His response is to draw a correlation to the manna of the wilderness. How did Israel benefit from the manna? They applied it to themselves (by eating it). How was Israel to benefit from Christ? They were to apply Him to themselves (by believing in Him).
Jesus is either (1) adding a condition to eternal life, or (2) using a figure of speech to illustrate the importance of personal application. In other words, God’s sending of the manna provided no actual benefit for the individual unless he/she personally applied the manna. Likewise, God’s sending of the Messiah does not automatically provide the benefit of eternal life for the individual. Every person must apply Him – we must all believe in Him for ourselves.
We know Jesus is not adding an additional condition to eternal life because the context is replete with statements that there is only one condition (belief in Him). Also, John, in identifying the purpose of his entire Gospel, identifies the one condition as belief (20:30-31). Further, we understand He is using a figure of speech by His contrast and comparison with the manna. He likens Himself to the manna in some ways, and draws a contrast in other ways. Consequently, Jesus is advocating neither cannibalism nor transubstantiation. Instead He is advocating that all who would have eternal life must apply Him personally to their own lives – by belief in Him.