So the Lord will make himself known to the Egyptians, and in that day they will acknowledge the Lord. They will worship with sacrifices and grain offerings; they will make vows to the Lord and keep them. (Isaiah 19:21) (NIV)
God can change hearts and that's for sure. When the Lord makes himself known, they (Egypt)will acknowledge and they will worship is what Isaiah prophesied......How wonderful are his ways.
Sometimes he afflicts and then he heals, so that the arrogant may know that he is sovereign.
The Lord will strike Egypt with a plague; he will strike them and heal them. They will turn to the Lord, and he will respond to their pleas and heal them. (Isaiah 19:22) (NIV)
If the Lord wills, anyone, however hard hearted he/she may be, can be transformed in to a new person. All things are possible with God. He is El Shaddai; God Almighty. Praise be to his holy name.