Exodus 10:22 DBY

²⁰  And Jehovah made Pharaoh's heart stubborn, and he did not let the children of Israel go.

²¹  And Jehovah said to Moses, Stretch out thy hand toward the heavens, that there may be darkness in the land of Egypt -- so that one may feel darkness.

²²  And Moses stretched out his hand toward the heavens; and there was a thick darkness throughout the land of Egypt three days:

²³  they saw not one another, neither rose any from his place, for three days. But all the children of Israel had light in their dwellings.

²⁴  And Pharaoh called Moses and said, Go, serve Jehovah; only, let your flocks and your herds remain; let your little ones also go with you.