The 9th Chapter of the Gospel According to John ...tells of the disciples of Jesus, who had the advantage of being with Him while He walked on earth ...therefore, being present for real-time learning.

The disciples often saw that malady was a result of sin.

Most people view sin entering the world when the fruit of the tree of knowledge of good & evil was eaten ...which Adam & Eve were directed not to.

God confronted, "Have you eaten of of the tree?"

Adam dodges responsibility, "It's ma' lady ...da' lady ya gave ta me."

But, back to Jesus and the disciples, Jesus told them, "No."

The person had been blind from birth, so the disciples could not see how the person could have sinned before he was born ...and therefore become blind, so they asked if the parents had sinned.

Jesus said that it was not sin ...but, for the works of God to be manifest.