12 But the LORD hardened Pharaoh’s heart and he would not listen to Moses and Aaron, just as the LORD had said to Moses.
Pharaoh has been hardening his own heart during the previous plagues. He has chosen again and again to not listen to the Lord’s voice. Now the Lord hardens his heart. This plague involves skin boils. Imagine blisters all over your body, painful and oozing! YUK! The plagues have become more personal, touching on their bodies, not just the water or their living space. Their cattle have died and now their skin is erupting. But instead of listening to the Lord, Pharaoh hardens his heart. But this time the Lord responds with hardening of His own. This is a subtle shift in the action of God. Up to this point Pharaoh has been turning his back. Now the Lord responds with hardening. It is a sad state of affairs when someone hardens their heart toward the Lord. Even when facing the obvious work of God they chose to not listen. Their child can be saved from death in miraculous ways and they still don’t respond in submission and obedience. They stop up their ears and continue to believe that they are powerful, that they don’t need the Lord. We must be careful that we listen when the Lord speaks. If we stop listening, our hearts get hard. At some point, a point not determined by us, the Lord responds with a hardening. And even then, the Lord desires repentance. He wants Pharaoh to let the Hebrews go. He wants Pharaoh himself to respond in trust. Imagine if the leader of a nation were to be on fire for God what a great difference that could make for that nation. Imagine what a difference that would make if we were on fire for the Lord.
The Arnold Journey 