Exodus 11:4-6

King James Version

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

⁵ And all the firstborn in the land of Egypt shall die, from the first born of Pharaoh that sitteth upon his throne, even unto the firstborn of the maidservant that is behind the mill; and all the firstborn of beasts.

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