Note: Here is another suggestion for this section in John 6. The parallelism matches up Jesus’ two ‘Verily Verily…’ statements (A and A’) and the peoples’ two questions (B and B’) making Jesus’ explanation of the work of God (C) the central point.
A 25 And when they had found him on the other side of the sea, they said unto him, Rabbi, when camest thou hither? (26-27) Jesus answered them and said, Verily, verily, I say unto you, Ye seek me, not because ye saw the miracles, but because ye did eat of the loaves, and were filled. Labour not for the meat which perisheth, but for that meat which endureth unto everlasting life, which the Son of man shall give unto you: for him hath God the Father sealed.
B (28) Then said they unto him, What shall we do, that we might work the works of God?
C (29) Jesus answered and said unto them, This is the work of God, that ye believe on him whom he hath sent.
B’ (30-31) They said therefore unto him, What sign shewest thou then, that we may see, and believe thee? what dost thou work? Our fathers did eat manna in the desert; as it is written, He gave them bread from heaven to eat.
A’ (32-34) Then Jesus said unto them, Verily, verily, I say unto you, Moses gave you not that bread from heaven; but my Father giveth you the true bread from heaven. For the bread of God is he which cometh down from heaven, and giveth life unto the world. Then said they unto him, Lord, evermore give us this bread.