Why should you become stubborn, the way the Egyptians and Pharaoh were stubborn? Was it not after he had dealt ruthlessly with them that the Israelites were released and departed?
So Moses and Aaron went to Pharaoh and told him, “Thus says the Lord, the God of the Hebrews: How long will you refuse to submit to me? Let my people go to serve me.
But I will harden the hearts of the Egyptians so that they will go in after them, and I will receive glory through Pharaoh and all his army, his chariots and his horsemen.
The Lord said to Moses: On your return to Egypt, see that you perform before Pharaoh all the wonders I have put in your power. But I will harden his heart and he will not let the people go.
and the magicians said to Pharaoh, “This is the finger of God.” Yet Pharaoh hardened his heart and would not listen to them, just as the Lord had said. Fourth Plague: The Flies.