That the saying of Esaias 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? Therefore they could not believe, because that Esaias said again, He hath blinded their eyes, and hardened their heart; that they should not see with their eyes, nor understand with their heart, and be converted, and I should heal them. These things said Esaias, when he saw his glory, and spake of him. Nevertheless among the chief rulers also many believed on him; but because of the Pharisees they did not confess him, lest they should be put out of the synagogue: For they loved the praise of men more than the praise of God.
John 12:38-43 KJV

This was to fulfill the word of Isaiah the prophet: 'Lord, who has believed our message and to whom has the arm of the Lord been revealed?' For this reason they could not believe, because, as Isaiah says elsewhere: 'He has blinded their eyes and deadened their hearts, so they can neither see with their eyes, nor understand with their hearts, nor turn--and I would heal them.' Isaiah said this because he saw Jesus' glory and spoke about him. Yet at the same time many even among the leaders believed in him. But because of the Pharisees they would not confess their faith for fear they would be put out of the synagogue; for they loved praise from men more than praise from God.
John 12:38-43 NIV