“So the Jews grumbled about him, because he said, “I am the bread that came down from heaven.” 42 They said, “Is not this Jesus, the son of Joseph, whose father and mother we know? How does he now say, ‘I have come down from heaven’?” 43 Jesus answered them, “Do not grumble among yourselves. 44 No one can come to me unless the Father who sent me draws him. And I will raise him up on the last day. 45 It is written in the Prophets, ‘And they will all be taught by God.’ Everyone who has heard and learned from the Father comes to me— 46 not that anyone has seen the Father except he who is from God; he has seen the Father. 47 Truly, truly, I say to you, whoever believes has eternal life. 48 I am the bread of life. 49 Your fathers ate the manna in the wilderness, and they died. 50 This is the bread that comes down from heaven, so that one may eat of it and not die.” (John 6:41-50 (ESV)
The Jews are struck by unbelief. Jesus is saying that he is the bread that came down from heaven. He is this bread that endures to eternal life, the word of God by which man lives, because he does not live by bread alone. The Jews pick up on something right away. Jesus is claiming to have come down from heaven. They don’t think this can be true. They watched him grow up, they know his parents. They figure he was born the same way anyone was, and conceived that way too. If he had come down from heaven he should have come in the way of angels, and inexplicably landed among them like Marvin the Martian. But had all that occurred he would not be able to save us from our sins. And the fact that he was born from a woman and grew up amongst us does not nullify the idea that he is God. He came down from heaven to live our life for us, so that he could die in our place and be raised for our justification. It is in his death and resurrection that we are given eternal life, and it is on account of his death and resurrection that he is the bread of life. By believing in him, then we have life.
“This is the bread that comes down from heaven, so that one may eat of it and not die.” Eating and believing are interrelated, in that those who believe will eat. This has been a point of contention in Lutheran circles now for quite some time. Was Jesus talking of the Lord’s Supper here? Was he maintaining that this was something a person had to do in order to be saved? Or did the eating he mentioned here mean merely to believe. Much of this contention centers around Luther’s argumentation with Zwingli at the Colloquy of Marburg. A person can read the transcripts of that in Sasse’s “This is my Body.” Luther did not wish to debate Zwingli on the grounds of John 6, but on the words of institution. So for the sake of argumentation he more or less agreed with Zwingli that here the word to eat was referring to the belief of a person, and said that this was not talking about the Lord’s Supper. The Reformed believe that eating is to believe and only to believe and that this is talking about the supper. I say we are best to leave that historical event alone when considering John 6. The argumentation for what the Lord’s Supper is does rest with the Words of Institution, and that is where the argument needed to be fought. John 6 is sloppier than the concrete Words of institution. That doesn’t mean John 6 isn’t about the Lord’s Supper. But how one views the Lord’s Supper is going to affect the way one reads John 6. The way one reads John 6 is not the determining factor in the understanding of the Lord’s Supper. It’s a horse and cart thing that Zwingli had confused. John wrote this gospel to people who celebrated the Lord’s Supper every Sunday. There is no way this would not influence both John’s reflections on the word’s Jesus spoke here, or the interpretation the people had concerning these words. We will be getting into that more, later. Suffice it for now to say that if one believes Jesus, he will take eat and he will take drink, and he will believe that in the eating and drinking he has the forgiveness of sins and eternal life. If we were going to go with Chemnitz'es threefold understanding of to eat here, we would realize that we can’t eat “spiritually” without also eating sacramentally. To deny the import of Christ’s word in the Words of Institution is to deny Christ in one way or another, usually it comes down to denying he is God, that he came down from heaven. The thought is that it is impossible for Christ to be bodily present in the sacrament. And once you have said something is impossible for Christ to do, you have denied he is God, for with God all things are possible. Though sometimes it comes down to denying Jesus was a man, and therefore he has no body to be present in the Lord’s Supper. But that is a rare belief today. I will say, that my studies of Sasse and Giertz reveal that both of those two most influential theologians in the 20th century Lutheranism did believe that Jesus was talking of the Lord’s Supper here. This despite what “The People’s Commentary” might have to say on the matter.