Exodus 10:21-23

And JEHOVAH saith unto Moses, ‘Stretch out thy hand towards the heavens, and there is darkness over the land of Egypt, and the darkness is felt.’ And Moses stretcheth out his hand towards the heavens, and there is darkness — thick darkness in all the land of Egypt three days; they have not seen one another, and none hath risen from his place three days; and to all the sons of Israel there hath been light in their dwellings.’