So they said to him, "What sign can you do, that we may see and believe in you? What can you do? Our ancestors ate manna in the desert, as it is written: 'He gave them bread from heaven to eat.'" So Jesus said to them, "Amen, amen, I say to you, it was not Moses who gave the bread from heaven; my Father gives you the true bread from heaven. For the bread of God is that which comes down from heaven and gives life to the world." So they said to him, "Sir, give us this bread always." Jesus said to them, "I am the bread of life; whoever comes to me will never hunger, and whoever believes in me will never thirst. (Jn 6:30-35)
People ask for a sign. They had eaten the bread which Jesus had multiplied. They wanted to make him a king and they went after him to be with him and to receive from him favours. Yet they ask for a sign. They are ready even to accept that their ancestors ate manna in the desert which was from above. They are ready to believe in the religion of Moses.
Jesus corrects the views of the people regarding the religion. The bread that the ancestors ate was from the Father. It was not the work of Moses or anyone else. Bread of heaven is from the father and the quality of the bread from heaven is that it is life giving. It gives life to the whole world. It is not for an individual or for a group of people or for a nation. Bread of heaven is for the whole world. It is for all.
Jesus makes one of the main affirmations about himself saying that he is the bread from heaven. By this he implies that he had come from heaven and that too he is sent by the father. Since he is from the Father he is the one who is life giving. So the people who believe in him and who come to him and who want to be his follower are the people who receive this bread from heaven.
