John 9:21, commentary and pictures

The speakers are the parents of the man born blind, and what they are willing to affirm is that he is their son and that he was born blind. Beyond that they profess not to know by what means he now sees or who opened his eyes. Because he is of age, an adult old enough to answer for himself, they tell their questioners to ask him and let him speak for himself, thus shifting responsibility to him. Their refusal to say more comes from fear of the Jewish authorities, who had agreed that anyone who confessed Jesus as the Christ should be expelled or excluded from the synagogue.

The healed man himself did not know who had healed him until Jesus revealed Himself to him as the Son of God, and then the man worshiped Him. The questioning around this answer exposes prejudice and unbelief, in that the Pharisees resisted convincing evidence of Christ's divine mission and opposed even the man who had been healed.

The healing itself is the work of Christ as the compassionate Shepherd seeking to save the man. That man was one whom the self-righteous Pharisees treated with contempt.