John 12:37-41 But although He had done so many signs before them, they did not believe in Him, that the word of Isaiah the prophet might be fulfilled, which he spoke: "Lord, who has believed our report? And to whom has the arm of the LORD been revealed?" Therefore they could not believe, because Isaiah said again: "He has blinded their eyes and hardened their hearts, Lest they should see with their eyes, Lest they should understand with their hearts and turn, So that I should heal them." These things Isaiah said when he saw His glory and spoke of Him.
At a conference I attended a few years back, the speaker was a well known defender of the Christian faith. In his experience on college campuses and in public debates, he has found that, no matter how persuasive the arguments and evidence for Christ, someone who is committed to unbelief is not going to budge. Question: “If you knew with absolute certainty that God exists, would you believe Him?” Answer: “No!” Question: “If you knew beyond a shadow of a doubt that Jesus rose from the dead, would you place your faith in Him?” Answer: “Absolutely not!”
What does that tell us? The problem for many unbelievers is not lack of evidence or the absence of impeccable reasons for belief in Jesus--the issue is a spiritual one. The rebellious human heart wants one thing and one thing only: autonomy. The word autonomy comes from a Greek word which means “to be a law unto oneself.” For unbelievers the idea that one day they are going to give account to God for their actions is abhorrent. For them, belief in God is too restrictive—it gets in the way of their pursuit of happiness. Such people are so committed to independence from God that they would rather give up their rationality than to exercise faith in Him.
This is what the Apostle John is saying as he summarizes the earthly ministry of Jesus Christ. Jesus had performed many indisputable miracles. These signs clearly and unequivocally revealed to them that God the Son was present among them. Yet, their response was large scale unbelief.
This was not a surprise to John, however, for in the Old Testament, the people of Israel responded to the mighty works of Yahweh in the same way. John cites Isaiah 53:1 and Isaiah 6:9-10 to show that unbelief was the result of hardness of heart. In saying this, John is summarizing the entire first half of the Gospel, for in John 1-12, the major theme is that the Light had come into the world through the Person of Jesus. This brought about two diametrically opposing responses—belief or unbelief. An individual was either going to open his heart to receive the light, or he was going to close his heart and repel it.
Please observe the stages. John first says that “they did not believe in Him” (12:37). Then he says, “They could not believe” (12:39). When a person continually rejects the light, a gradual hardening sets in, and there comes a point where the heart is no longer responsive. God then comes along and ratifies that condition by judicially blinding their eyes and hardening their hearts. That is a terrible spiritual condition!
One only has to observe how the Sanhedrin, made up of the Pharisees and Sadducees, responded to the raising of Lazarus from the dead. Rather than repenting and turning to Christ, they plotted how to put Him to death because they were afraid they would lose their positions of authority (John 11: 48)
For these reasons, let us be sure to have tender hearts that are open to the Light of Christ, so that we may receive Him and live.