Exodus 10:17-20

Now therefore forgive, I pray thee, my sin only this once, and entreat Jehovah your God, that he may take away from me this death only. And he went out from Pharaoh, and entreated Jehovah. And Jehovah turned an exceeding strong west wind, which took up the locusts, and drove them into the Red Sea; there remained not one locust in all the border of Egypt. But Jehovah hardened Pharaoh’s heart, and he did not let the children of Israel go.