GOD, Pharaoh won't let your people go! The past nine plagues have not changed his mind, you need to do something.
Then the Lord said to Moses: “I will bring one more plague on Pharaoh and Egypt. After that he will be certain to force all of you out of here."
"The Lord says: About midnight I will go out among the Egyptians. Every firstborn son in Egypt will die, from the firstborn of Pharaoh who rules the land, to the firstborn children of female slaves who use their handmills."
Then they are to take some of the blood and put it on the sides and tops of the doorframes of the houses where they eat the lambs.
The blood will be a sign for you on the houses where you are; and when I see the blood, I will pass over you. No destructive plague will touch you when I strike Egypt.