The symbol of “bread” is misunderstood by the people. They respond with unbelief. They grumble at Jesus’ claim that he is the bread of life and has come down from heaven. They protest that they “know” where Jesus comes from, they are aware of his antecedents. Even as they make such a statement, they are unaware of its error. They “think” they know, but in reality do not know.
Jesus addresses the crowd and asks them to stop their grumbling and then repeats the promise made earlier of resurrection on the last day for the ones who will believe. To reiterate the point that he makes, Jesus appeals to scripture and specifically to the prophets. “And they shall all be taught by God” refers to the initiative that God takes. The emphasis is on God who does the teaching. This means that Jesus’ commission is divinely ordained and not from humans. If the ones who hear realize this, then they will come to Jesus and they will have learnt correctly. This means that, while God does take the initiative, humans are responsible for responding accurately.
Jesus shares a unique relationship with the Father and is the only one who has seen Him. Those who learn have to learn to see the Father in Jesus. They have to learn that it is in Jesus that they have eternal life and that he is indeed the Bread of Life.
By using the distancing “your ancestors”, Jesus makes a contrast between the manna that they ate and the bread of life that he gives. The manna their ancestors consumed could not result in saving them from death, but the bread that Jesus gives results in a person living forever. This is because the bread that Jesus gives is living bread, a life giving bread. The bread that he gives for the life of the world is his flesh. This can mean, on one hand, the incarnation, where the Word became flesh, but on the other, can refer to his death on the cross, when he will give his life for the life of the world.
The purpose of Jesus’ coming into the world was to reveal the Father as God who wanted to save all people. This results in God taking the initiative in the tangible way of sending his son to become flesh for all. Even as God takes the initiative, he leaves humans free to respond to his act of love. Humans always have a choice when it comes to the gifts that God gives. They can accept them or reject them. Acceptance means life, rejection means death. There is no middle way.