Exodus 8:3 The Nile shall swarm with frogs that shall come up into your house and into your bedroom and on your bed and into the houses of your servants and your people, and into your ovens and your kneading bowls. 4 The frogs shall come up on you and on your people and on all your servants...13 And the Lord did according to the word of Moses. The frogs died out in the houses, the courtyards, and the fields. 14 And they gathered them together in heaps, and the land stank.
But again and again Pharaoh hardens his heart.
As we read on, we find out why Pharaoh's heart was so tough...
Exodus 9:16 But for this purpose I have raised you up, to show you my power, so that my name may be proclaimed in all the earth.
Pharaoh had a "free" will, and yet God had raised him up, a stubborn, hard-hearted king, that God would receive world-wide glory in the midst of Pharaoh's obstinance. In some sense, the more stubborn Pharaoh is, the more glory God receives. And even today, there's not many places that you could go where people haven't heard the story about the Ten Plagues.
Lord, I pray that you would continue to make your name renown among all the nations.