The Exodus account of that classic contest of wills—between Moses acting under his patron, the God of Israel, and Pharaoh, ruler of Egypt—contains a strange, but repeated reference to the hardening of Pharaoh’s heart. Just when Moses thinks he has demonstrated Yahweh’s power to Pharaoh and Pharaoh has agreed to let the Israelite slaves leave Egypt, Yahweh hardens Pharaoh’s heart and Pharaoh changes his mind, thus calling forth further plagues.
Hardening the heart can, of course, simply be a poetic way of describing Pharaoh’s stubbornness. But it takes on a much deeper meaning when we understand the concept of a hardened heart against the background of ancient Egyptian culture and its mythology.
This should not be surprising because, as is well known, a good deal of the Exodus story is illuminated by its authentic Egyptian setting. The author clearly understood the Egyptian world, and especially Egyptian religion, from the inside, for the story is nothing so much as a contest between the powers of Yahweh and the powers of the Egyptian pantheon, including the Pharaoh himself.