I love the story of Jesus healing the man born blind in John 9. In that account, Jesus puts clay on the man's eyes and tells him to wash in the Pool of Siloam. When he does, his sight is restored and his neighbors are astounded. After confirming that he was the formerly blind man, they ask him, "How did it happen?" He tells them the story and they take him to a group of Pharisees who ask him, "How did it happen?" The Pharisees take him to his parents and ask them, "How did it happen?" The parents refer them back to their son. So, the Pharisees ask again (yes, you guessed it), "How did it happen?" His response is classic.
"I have told you already, and you would not listen. Why do you want to hear it again? Do you also want to become his disciples?” And they reviled him, saying, “You are his disciple, but we are disciples of Moses. We know that God has spoken to Moses, but as for this man, we do not know where he comes from.” The man answered, “Why, this is an amazing thing! You do not know where he comes from, and yet he opened my eyes. We know that God does not listen to sinners, but if anyone is a worshiper of God and does his will, God listens to him. Never since the world began has it been heard that anyone opened the eyes of a man born blind. If this man were not from God, he could do nothing.”
In other words, the blind man was saying, "Are you kidding me?" It's a phrase reserved for ... well ... idiots! And in this case, the man was quite frustrated with their continued questioning. After telling them the story so many times, the Pharisees didn't need to hear the message again; they already knew what had happened. By that time, they just needed to choose whether they would believe or not. But they had already rejected Jesus and were spiritually blind to anything he would do or say. Sadly, many people are like that today. They stagger through this spiritually dark world unwilling to turn to Jesus, the Light of the World, who can open their eyes to the truth. But until their eyes are opened by him, they will never understand.