In John 12:37-40, John related that the people saw Jesus' miracles, but still did not believe on him. John said this unbelief was a fulfillment of Isaiah 53 ("Lord, who has believed our report?"). Isaiah was saying, in a way, Lord, nobody believes what I'm preaching. Then, in v.39, John says "Therefore, they could not believe", and referred back to Isaiah 6, where God told Isaiah to preach, but that no one would listen. God explained why they wouldn't believe. It was because he had blinded their eyes and hardened their hearts. God explained to Isaiah that this was so they should not see or understand. Then God told Isaiah that he did this so they would not be converted. How would you like it if, when God called you to preach, he warned you that no one would ever be saved under your preaching? If I read the book of Isaiah right, he preached for many years and never had a convert. He must have been frustrated because he cried out to God "they won't believe.!" To me, the passage in John and the related passages in Isaiah do not say that God blinded and hardened because they would not believe. They say that they could not believe because of the blinding and hardening. Okay, who wants to take a crack at explaining this passage further or explaining it away?