Exodus 11:3-5

New Revised Standard Version, Anglicised Catholic Edition

³ The Lord gave the people favour in the sight of the Egyptians. Moreover, Moses himself was a man of great importance in the land of Egypt, in the sight of Pharaoh’s officials, and in the sight of the people.

⁴ Moses said, ‘Thus says the Lord: About midnight I will go out through Egypt. ⁵ Every firstborn in the land of Egypt shall die, from the firstborn of Pharaoh who sits on his throne to the firstborn of the female slave who is behind the handmill, and all the firstborn of the livestock.