Exodus 10:19-21

American Standard Version

¹⁹ 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. ²⁰ But Jehovah ^[a]hardened Pharaoh’s heart, and he did not let the children of Israel go.

²¹ And Jehovah said unto Moses, Stretch out thy hand toward heaven, that there may be darkness over the land of Egypt, ^[b]even darkness which may be felt.