Jesus is the Messiah whose life, death, and resurrection are God's saving act for humanity More calls himself “the light of the world” and demonstrates the truth of his claim by bringing light physically and spiritually to a man born blind.
Jesus sees a man who was born blind, and the disciples ask him about the cause of the blindness (9:1-2). The disciples assume that the blindness must be a form of divine punishment for sin. For them, the question is whether the man himself had sinned—presumably in the womb before birth—or whether his parents had sinned, with the result that their child was born blind. Their way of thinking is based in part on some biblical texts that assume a child could be punished for the sins of the parents (Exodus 20:5).
Jesus, however, shifts the frame of reference. He insists that the paradigm of sin and punishment does not fit this case of congenital blindness. He also refuses to speculate further about what caused the blindness and shifts the focus to what can be done about the blindness.
Some translations paraphrase the passage and obscure the dramatic shift that Jesus makes. For example, the NRSV has Jesus say that “he was born blind” so that God’s works might be revealed in him (John 9:3). But the words “he was born blind” were added by the translator. They do not appear in Greek. A word-for-word translation is, “Neither this man nor his parents sinned, but in order that the works of God might be revealed in him, we must do the works of him who sent me while it is day.” Jesus accepts the blindness as a given and refuses to speculate about what caused it. For him, the question is how to address the situation so that God’s works will be done in it.
Jesus does not heal the man immediately. Rather, he puts mud on the man’s eyes and tells him to go and wash. Jesus’ words prompt the man to go, even before he has received his sight, and for much of the chapter the man will bear witness to a Jesus whom he has never seen. That makes the story especially valuable for readers living in later generations, since they too must bear witness to a Jesus whom they have never seen apart from the eyes of faith.