Exodus 10:22-23

22 Moshe reached out his hand toward the sky, and there was a thick darkness in the entire land of Egypt for three days.
23 People couldn't see each other, and no one went anywhere for three days. But all the people of Isra'el had light in their homes.
Complete Jewish Bible Copyright 1998 by David H. Stern. Published by Jewish New Testament Publications, Inc. All rights reserved. Used by permission.