John 12:37-41 : But though he had done so many signs before them, yet they didn’t believe in him, that the word of Isaiah the prophet might be fulfilled, which he spoke, “Lord, who has believed our report? To whom has the arm of the Lord been revealed?” For this cause they couldn’t believe, for Isaiah said again, “He has blinded their eyes and he hardened their heart, lest they should see with their eyes, and perceive with their heart, and would turn, and I would heal them.” Isaiah said these things when he saw his glory, and spoke of him.
The Bible says here that the reason that the people didn’t believe was because they couldn’t. God had, blinded their eyes and hardened their hearts so they could not see or understand. No amount of reasoning will convince a person who’s inner eyes are blinded and who’s heart has been hardened by God.
Blinding someone from seeing the truth doesn’t seem like a thing that God would do. Why would He purposefully use his effort to speak to someone He has already made unable to understand? For one, God’s word must come true. In His word, He said that Jesus would come and speak the truth to the people, and that the people would reject Him. Also, God must always be in charge and will never give His power to man. Man may think He has the power of a god, but really, man only does exactly what God wants him to do. That’s an important lesson for mankind to learn, and things like this teach this lesson.
From the perspective of the people, they did exactly what they wanted to do. The people don’t see themselves as blind. In fact they seemed to believe that they were quite intelligent in their knowledge of the law. Their actions, however, show that they were nearly insane. Attempting to kill a man raised from the dead being one of the main examples of this insanity. Jesus, however, acted in love by continuing to deliver a message of hope to the closed minded. Jesus sinless perfection was made clear by His continuing to do what was right while being surrounded by many reasons to give up.
Finally, if you understand what Jesus has done and what it means, your eyes have been opened by God. It is God who has saved you personally. Seeing what it is like to be blind helps us to understand what it means when God allows us to see. That is what He has done for us as believers and this is the reason why we serve Him. He freely gave to us without our help at all, now we understand and can freely give to Him, not to repay Him, but because we really are happy and thankful for what God has done and want to give like He has.