Exodus 11:4-6

Darby Translation

⁴ And Moses said, Thus saith Jehovah: About midnight I will go out into the midst of Egypt.

⁵ And all the firstborn in the land of Egypt shall die, from the firstborn of Pharaoh who sitteth on his throne, even unto the firstborn of the bondwoman that is behind the mill; and all the firstborn of cattle.

⁶ And there shall be a great cry throughout the land of Egypt, such as there hath been none like it, nor shall be like it any more.