Matthew Henry Commentary John 12:37-43

"But though he had done so many signs before them, yet they believed not on him: that the word of Isaiah the prophet might be fulfilled, which he spake, Lord, who hath believed our report? And to whom hath the arm of the Lord been revealed? For this cause they could not believe, for that Isaiah said again, He hath blinded their eyes, and he hardened their heart; Lest they should see with their eyes, and perceive with their heart, And should turn, And I should heal them. These things said Isaiah, because he saw his glory; and he spake of him. Nevertheless even of the rulers many believed on him; but because of the Pharisees they did not confess [it], lest they should be put out of the synagogue: for they loved the glory [that is] of men more than the glory [that is] of God." — John 12:37-43 (ASV)

Observe the method of conversion implied here. Sinners are brought to see the reality of divine things, to have some knowledge of them, and to be converted and truly turned from sin to Christ as their happiness and true fulfillment. God will heal them. He will justify and sanctify them; He will also pardon their sins, which are like bleeding wounds, and mortify their corruptions, which are like lurking diseases.

See the power of the world in smothering convictions, due to concern for human praise or criticism. Love of human praise, when it is an ulterior motive in what is good, will make a person a hypocrite if religion is fashionable and brings social approval; and this same love of human praise, when it is a base principle in what is evil, will make a person an apostate if religion is unpopular and results in social disapproval.