John 6:28-31

28Then they asked him, “What must we do to do the works God requires?”

29Jesus answered, “The work of God is this: to believe in the one he has sent.” 30So they asked him, “What sign then will you give that we may see it and believe you? What will you do?

31Our ancestors ate the manna in the wilderness; as it is written: ‘He gave them bread from heaven to eat.’ Exodus 16:4; Neh. 9:15; Psalm 78:24,25 ”