John 9:3
Jesus answered, "Neither did this man sin, nor his parents; but, that the works of God might be revealed in him.
WEB
Jesus answered, Neither hath this man sinned, nor his parents: but that the works of God should be made manifest in him.
KJV
What John 9:3 means
Jesus tells his disciples that a man's blindness from birth was no punishment for anyone's sin, and that God was about to do something good and visible in his life.
Jesus and his disciples are walking through Jerusalem when they pass a man who has been blind since the day he was born. He is probably sitting by the road begging, since that was about the only way a blind man could live back then.
The disciples see him and ask Jesus a question that sounds strange to us but was common at the time: "Who sinned, this man or his parents, that he was born blind?" Many people assumed that suffering was God's payback for something someone had done wrong. So if a man was born blind, the blame had to land somewhere, either on his parents or, some thought, even on the man himself before he was born.
Jesus refuses the whole question. He says the blindness didn't come from this man's sin or his parents' sin. That doesn't make them perfect people. It means there is no line to draw from some wrongdoing to this man's darkness. Then he turns their attention forward, away from who is to blame and toward what God is about to do: this happened "so that the works of God might be displayed in him."
That line can sound as if God made the man blind just to stage a miracle later. The original Greek had no punctuation, though, and some readers join the end of this verse to the next one, so that Jesus says, in effect, "Neither he nor his parents sinned. But so that God's works can be shown in him, we have to do the work of the one who sent me while it is still day." Read that way, Jesus is less interested in explaining why the man suffers and more interested in what God is going to do about it, right now.
And that is exactly what happens. Jesus spits on the ground, makes a little mud, puts it on the man's eyes, and tells him to go wash in the pool of Siloam. The man goes, washes, and comes back able to see for the first time in his life.
The rest of the chapter follows the fallout. The religious leaders question the man, his parents, and the man again, and they end up throwing him out. By the end, the man who was born blind sees clearly who Jesus is, while the people who were sure they could see turn out to be the blind ones. So this verse sets up the whole story: a man everyone had written off as a sign of someone's sin becomes the place where God's goodness shows up in plain sight.