As he went along, he saw a man blind from birth. His disciples asked him, "Rabbi, who sinned, this man or his parents, that he was born blind?"
John 9:1-3
An important fact to understand about evil is that it always serves a purpose. Jesus makes that clear in this story of a man with congenital blindness, which was interpreted then, as it might be today, as evil; an unnecessary blight in the world. And notice how it is simply assumed that this evil is the result of sin; either the man or those responsible for his conception must be to blame for his condition. But Jesus points out that evil doesn’t always work that way. Sometimes evil is permitted by God so that He will receive glory, and indeed, by the time the dust fully settles around this blind man, he is worshipping God after having boldly confronted the religious leaders of his day who desired to lead him astray. Jesus’ own disciples make the mistake here of assigning blame to humanity for the presence of evil, failing the entire time to understand that evil, regardless of the cause, is the servant of God.
Romans