And I say unto thee, Let my son go, that he may serve me: and if thou refuse to let him go, behold, I will slay thy son, even thy firstborn.
Exodus 11:5
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.
Exodus 12:29
And it came to pass, that at midnight the LORD smote all the firstborn in the land of Egypt, from the firstborn of Pharaoh that sat on his throne unto the firstborn of the captive that was in the dungeon; and all the firstborn of cattle.
Psalm 78:51
And smote all the firstborn in Egypt; the chief of their strength in the tabernacles of Ham:
Psalm 105:36
He smote also all the firstborn in their land, the chief of all their strength.
Psalm 135:8
Who smote the firstborn of Egypt, both of man and beast.