Then Moses said, "Thus says the LORD: "About midnight I will go out into the midst of Egypt;
Exodus 11:4
Surrounding context
11:3 And the LORD gave the people favor in the sight of the Egyptians. Moreover the man Moses was very great in the land of Egypt, in the sight of Pharaoh's servants and in the sight of the people.
11:4 Then Moses said, "Thus says the LORD: "About midnight I will go out into the midst of Egypt;
11:5 and all the firstborn in the land of Egypt shall die, from the firstborn of Pharaoh who sits on his throne, even to the firstborn of the female servant who is behind the handmill, and all the firstborn of the animals.