Exodus 11:4-5

New American Standard Bible

⁴ Then Moses said, “This is what the Lord says: ‘About ^(A)midnight I am going out into the midst of Egypt, ⁵ and ^(B)all the firstborn in the land of Egypt shall die, from the firstborn of the Pharaoh who sits on his throne, to the firstborn of the slave girl who is behind the millstones; all the firstborn of the cattle as well.