The plagues that afflicted Egypt were immense and punishing. When you take in just how intense these events must have been, it's such a wonder that Pharaoh's heart continued to harden against Moses and the people. Then again, it's not really that hard to imagine. As individuals, as a nation, as a world, we feel powerful. We describe ownership to everything which is a denial of the Creator. With every hardship though we can be crushed and feel powerless, then our eyes may recognize Him.