Exodus 11:3-5

Authorized (King James) Version

³ And the Lord gave the people favour 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.

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 firstborn 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.