Exodus 8:19

Then the magicians said unto Pharaoh, This is the finger of God. They were forced to declare their impotence in the face of God's almighty power, to acknowledge that the God of the Hebrews was mightier than they. And Pharaoh's heart was hardened, and he hearkened not unto them; as the Lord had said. In spite of all the evidence, in spite of the confession of his wisest sorcerers, he persisted in his obstinacy. Even the blind children of this world are obliged to acknowledge occasionally that God's punishments strike the world, and yet they refuse to repent.