Exodus 10:21-23

The LORD said to Moses, “Stretch out your hand towards the sky, that there may be darkness over the land of Egypt, even darkness which may be felt.” Moses stretched out his hand towards the sky, and there was a thick darkness in all the land of Egypt for three days. They didn’t see one another, and nobody rose from his place for three days; but all the children of Israel had light in their dwellings.