"33 He said this to show by what kind of death he was going to die. 34 So the crowd answered him, “We have heard from the Law that the Christ remains for ever. How can you say that the Son of Man must be lifted up? Who is this Son of Man?” 35 So Jesus said to them, “The light is among you for a little while longer. Walk while you have the light, lest darkness overtake you. The one who walks in the darkness does not know where he is going. 36 While you have the light, believe in the light, that you may become sons of light.”
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."
John 12:33-41
The solemn words of this passage tell us two things: one is that there was a basic blindness upon the hearts of the people. They could not grasp what was being said. Their eyes were 'holden' that they could not see. The other thing is that, aware as they undoubtedly were of the prophetic Scriptures - the Messianic promises of the Old Testament, they obviously had never put two and two together, or realised that the glorious King Who was to come and the suffering Servant in Isaiah were one and the same Person. This is made very plain in 34. It is in this light that we must understand Jesus' words in 34, 35, spoken in reply to them. They constitute in fact His final appeal to the Jews. One can sense our Lord's urgency as He realised they were still blind in face of all that had been given them and all that had been revealed to them. It is as if He had said, 'The sands are running out for you, and there is not much time left, be up and doing, it is later than you think'. The last words of 36 are unspeakably solemn in this light, for they speak of His withdrawal from them. It is striking to note that from this point onwards, there was no further public ministry to them. This passage represents the final exposition of the words we have in the Prologue: 'He came unto His own, and His own received Him not'. The next chapter begins the second division of the gospel, our Lord's ministry to His own, who did receive Him. John quotes Isaiah confirming this solemn situation - a passage quoted also in the Synoptics, in relation to the parables of the kingdom. First they would not believe (37), in spite of all the signs and wonders they had witnessed; then finally they could not believe (39). The judgment on refusal to believe is finally inability to believe. How solemn!