Exodus 11:4-6

Revised Standard Version

⁴ And Moses said, “Thus says the Lord: About midnight I will go forth in the midst of Egypt; ⁵ and all the first-born in the land of Egypt shall die, from the first-born of Pharaoh who sits upon his throne, even to the first-born of the maidservant who is behind the mill; and all the first-born of the cattle. ⁶ And there shall be a great cry throughout all the land of Egypt, such as there has never been, nor ever shall be again.