The word of GOD has great power

Exodus 9:22-35
Moses stretch out his hand (staff) toward the sky, the plague of Hail. Number 7
Plague of Boil- -Take handfuls of soot from a furnace and toss it into the air.
The Plague of Gnats- stretch out staff and strike the dust of the ground
The plague of Blood and Frogs- stretch out staff over the water
The plague of Files, Livestock- The Load said
7th plague- Hail. It was the worst storm in all the land of Egypt since it had become a nation.
Thsi time, Pharaoh confessed The Load is right, and I and my people are in the wrong. Pharaoh permitted "Moses and his people go; you don't have to stay any longer"
Barley and flax were destroyed, wheat and spelt were not destroy, because they ripen later.
Moses answered to Pharaoh, I know you and your officials still do not fear the Load GOD. When Moses spread out his hands toward the Load, the thunder, hail and rain no longer poured down on the ground, Pharaoh and his officials hardened their heart.
Why?
This time God struck Egyptian the field, destroyed the flex and barley and people in the field.
First stage let Egyptian felt very inconvenient. From 5th plague took life of livestock. 7th plague destroyed field.
When loss of Egyptian more heavy, Pharaoh like let Moese leave, but still harden their heart.
How?
People's heart still harden, unless they counter great pain or hurt. I hope I have the sensitivity to the sin and wrong action.
God did his work through Moses staff, The Load even can do anything without anything action , just God say a word.