I will harden Pharaoh's heart - Exodus 11

Exodus 11:9 Then the Lord said to Moses, "Pharaoh will not listen to you, so that My wonders will be multiplied in the land of Egypt." 10Moses and Aaron performed all these wonders before Pharaoh, yet the Lord hardened Pharaoh's heart, and he did not let the sons of Israel go out of his land.Pharaoh's not the problem. The Lord hardened his heart. The Lord made it impossible for any human effort to overcome.If the Lord didn't harden his heart, then Pharaoh would have let them go much earlier, and exodus wouldn't have become such a famous scene in history.It's interesting to see that after frustrations and human limits, there're usually great miracles. Like in Judges 13:2"...Manoah's wife was barren and had borne no children..." It's unnatural for Israelites not to have children. But when there was an obstacle, a miracle appeared: Samson was born with supernatural power, and he became the next judge. Then Abraham and Sarah, Hannah,Elizebeth...This speaks to me that unusual difficulties and obstacles are often signs of unusual miracles and great wonders.God is often behind the difficulties to get people's attention for Himself to intervene.