Originally Posted by lumbingmi
And the LORD said to Moses, “When you go back to Egypt, see that you do all those wonders before Pharaoh which I have put in your hand. But I will harden his heart, so that he will not let the people go.
Yes when God did all those wonders before Pharaoh, it made Pharaoh mad because he couldn't defeat God's wonders so it harden his heart and held on to people even more.
God didn't touch his heart and made it hard or said a magic word and Pharaoh became a evil man. God only perform those wonders and warned Moses that his wonders will get Pharaoh angry
and to be prepared for a long struggle to free the people.