Exodus 12:29-30

The Deliverance from Egypt

12:29 It happened at midnight – the Lord attacked all the firstborn in the land of Egypt, from the firstborn of Pharaoh who sat on his throne to the firstborn of the captive who was in the prison, and all the firstborn of the cattle. 12:30 Pharaoh got up in the night, along with all his servants and all Egypt, and there was a great cry in Egypt, for there was no house in which there was not someone dead.

Psalms 105:36

105:36 He struck down all the firstborn in their land,

the firstfruits of their reproductive power.