John 12:39

Therefore they could not believe,.... God had determined to leave them to the blindness and hardness of their hearts, and to deny them his grace, which only could cure them of it, and enable them to believe: he had foretold this in prophecy, and they were manifestly the persons spoken of; and therefore considering the decrees of God, the predictions of the prophet, and the hardness of their hearts, they were left unto, it was morally impossible they should believe,

because that Esaias said again, in Isaiah 6:9.