When Jesus had said these things, he departed and hid himself from them.37 Though he had done so many signs before them, they still did not believe in him, 38 so that the word spoken by the prophet Isaiah might be fulfilled:
“Lord, who has believed what he heard from us,
and to whom has the arm of the Lord been revealed?”
39 Therefore they could not believe. For again Isaiah said,
40 “He has blinded their eyes
and hardened their heart,
lest they see with their eyes,
and understand with their heart, and turn,
and I would heal them.”
41 Isaiah said these things because he saw his glory and spoke of him.42 Nevertheless, many even of the authorities believed in him, but for fear of the Pharisees they did not confess it, so that they would not be put out of the synagogue; 43 for they loved the glory that comes from man more than the glory that comes from God.
44 And Jesus cried out and said, “Whoever believes in me, believes not in me but in him who sent me. 45 And whoever sees me sees him who sent me. 46 I have come into the world as light, so that whoever believes in me may not remain in darkness. 47 If anyone hears my words and does not keep them, I do not judge him; for I did not come to judge the world but to save the world. 48 The one who rejects me and does not receive my words has a judge; the word that I have spoken will judge him on the last day. 49 For I have not spoken on my own authority, but the Father who sent me has himself given me a commandment—what to say and what to speak. 50 And I know that his commandment is eternal life. What I say, therefore, I say as the Father has told me.”
“God appointed the prophet to preach to the inhabitants of Judah but warned him in advance that his mission would not be successful. The verbs as given in Isaiah 6:9-10 are imperatives. Isaiah was told to announce his message even though it merely hardened the hearts of those who heard him. God offered the opportunity of faith, but the very offer made the recipients of it more obstinate. John interprets the prophecy by its effect rather than by its intention. It was not God’s desire to alienate his people; but without the offer of faith and repentance, they would never turn to him anyway. The cumulative effect of unbelief is a hardened attitude that becomes more impenetrable as time progresses.”
- What was the reason the Jews could not believe in Jesus despite all the miraculous signs he had done?
- How can continuing to see the work of God and yet refusing to believe cause a person to become blinded and hardened?
- Are there some ways or areas of my life in which I am allowing my heart to harden because I am persisting in not responding to God?
- What was the problem of these leaders who would not confess their faith “for fear of the Pharisees […] so that they would not be put out of the synagogue”?
- What fears prevent me from making my faith public?
- What has been my attitude toward the word of God that “is eternal life” when believed, but “will judge [me] on the last day” if rejected?
 Frank E. Gaebelein, Expositor’s Bible Commentary CD (Grand Rapids: Zondervan Pub. House, 1992), notes for chapter 12.