Then the Lord said to Moses, "Stretch out your hand toward heaven, and there will be darkness over the land of Egypt, a darkness that can be felt."
References for Exodus 10:21
So Moses stretched out his hand toward heaven, and there was thick darkness throughout the land of Egypt for three days.
One person could not see another, and for three days they did not move from where they were. Yet all the Israelites had light where they lived.
Pharaoh summoned Moses and said, "Go, worship the Lord. Even your families may go with you; only your flocks and your herds must stay behind."
Moses responded, "You must also let us have sacrifices and burnt offerings to prepare for the Lord our God.
References for Exodus 10:25
Even our livestock must go with us; not a hoof will be left behind because we will take some of them to worship the Lord our God. We will not know what we will use to worship the Lord until we get there."
But the Lord hardened Pharaoh's heart, and he was unwilling to let them go.
Pharaoh said to him, "Leave me! Make sure you never see my face again, for on the day you see my face, you will die."
"As you've said," Moses replied, "I will never see your face again."