What does John 9:32 mean?

So far as we know, the man speaking these words is the first in human history to be cured of lifelong blindness. Jesus' miracle not only showed His godly power (John 12:37–38), but it also fulfilled prophecies about the Messiah (Isaiah 29:18; 35:5; 42:7). In Scripture, concepts such as light and darkness, or sight versus blindness, were used to represent spiritual matters. In prior verses, the recently-healed man has pointed out that the miraculous healing Jesus performed on him ought to be evidence that Jesus is from God (John 9:30–31).

Further, Jesus' miracle is unique. Jesus has done something supernatural, but even further, He has done something no other prophet or priest in Israel's history had ever done. Earlier, the scribes and Pharisees interrogating this man rejected Jesus on the grounds that they didn't know where He'd come from (John 9:29). This response, from the one who'd been healed, points out that such evasions are just excuses to be prejudiced. They are not sincere, valid answers.

The "bottom line" of the formerly blind man's argument comes in the next verse (John 9:33), in simple and common-sense terms.