Exodus 10:22 YLT

²⁰  and Jehovah strengtheneth the heart of Pharaoh, and he hath not sent the sons of Israel away.

²¹  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.'

²²  And Moses stretcheth out his hand towards the heavens, and there is darkness -- thick darkness in all the land of Egypt three days;

²³  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.'

²⁴  And Pharaoh calleth unto Moses and saith, 'Go ye, serve Jehovah, only your flock and your herd are stayed, your infants also go with you;'