They have not known nor understood: for he hath shut their eyes, that they cannot see; and their hearts, that they cannot understand.
Have you ever known someone who could deny facts even when faced with clear and undeniable proof? Yep, me too. Plenty of them.
When I came across the verse in Isaiah 44, about twelve years ago, I highlighted it in my Bible and wrote in the margins: this was me! And it was. For so many years - even after leaving the FOC - I believed they were God's only chosen people. Now I know that is obviously untrue. But I'm not so distantly removed to forget how anyone could think that way.
In the New Testament, the scales fell from the Apostle Paul's eyes in the eighteenth verse of Acts 9:
And immediately there fell from his eyes as it had been scales: and he received sight forthwith, and arose, and was baptized.
Did you know that all snakes have scales covering their eyes? They're designed that way for protection, since they lack eyelids.