Exodus 10:16-20

16Then Pharaoh hurried to call for Moses and Aaron, and he said, “I have sinned against the Lord your God and against you.

17Now therefore, please forgive my sin only this once [more], and pray and entreat the Lord your God, so that He will remove this [plague of] death from me.”

18Moses left Pharaoh and entreated the Lord.

19So the Lord shifted the wind to a violent west wind which lifted up the locusts and drove them into the Red Sea; not one locust remained within the border of Egypt.

20But the Lord hardened Pharaoh’s heart [so that it was even more resolved and obstinate], and he did not let the Israelites go.