What does John 9:16 mean?

Jesus' miracles are meant to prove that He is the Promised One: the Messiah. In the Old Testament, curing blindness is given as one such sign (Isaiah 29:18; 35:5; 42:7). Jesus has done that, granting sight to a man blind his entire life (John 9:1–7). Many in the crowd are shocked. Some doubt whether the now-seeing beggar is the same person (John 9:8–9). Since this event is sensational and occurred on a Sabbath day (John 9:14), the people bring the man to be interviewed by the Pharisees (John 9:15).

During Jesus' earthly ministry, Pharisees had a very positive reputation. They were extremely moral, living by a strict set of rules which had grown out of their traditions. Those traditions were aimed at "protecting" obedience to the law of Moses. In practice, however, the Pharisees treated those traditions as if they were equal to the actual Word of God. This resulted in a cold legalism and the arrogance of an "us-versus-them" version of spirituality.

Even when faced with a miracle, these men define right, wrong, good, and evil according to whether the messenger agrees with their interpretations. Unfortunately, this is a common problem even today. Many groups choose a "pet doctrine"—a day of worship, a translation of the Bible, and so forth—and use that as their first test of truth. Those who disagree with that stance are immediately dismissed as sinners, heretics, or false prophets. In effect, this makes their tradition the real "god" of that sect: blinding them even to miraculous evidence of the truth.