Exodus 10:19-21

19So the Lord shifted the wind to a very strong west wind which took up the locusts and drove them into the 1Red Sea; not one locust was left in all the territory of Egypt. 20But 2the Lord 3hardened Pharaoh’s heart, and he did not let the sons of Israel go.

21Then the Lord said to Moses, “4Stretch out your hand toward the sky, that there may be darkness over the land of Egypt, even a darkness 5which may be felt.”