John 6:24-35
When the people saw that neither Jesus nor his disciples were there, they got into boats and crossed to Capernaum to look for Jesus. When they found him on the other side, they said to him, “Rabbi, when did you come here?” Jesus answered: “I tell you most solemnly, you are not looking for me because you have seen the signs but because you had all the bread you wanted to eat. Do not work for food that cannot last, but work for food that endures to eternal life, the kind of food the Son of Man is offering you, for on him the Father, God himself, has set his seal.”
They then said to him, “What must we do if we are to do the works that God wants?” Jesus gave them this answer, “This is working for God: you must believe in the one he has sent.” So they said, “What sign will you give to show us that we should believe in you? What work will you do? Our fathers had manna to eat in the desert; as scripture says: He gave them bread from heaven to eat.”