Genesis 49:3

Reuben, thou {art} my firstborn, my might, and the beginning of my strength, the excellency of dignity, and the excellency of power:

Hebrews 11:28

Through faith he kept the passover, and the sprinkling of blood, lest he that destroyed the firstborn should touch them.

Psalms 136:10

To him that smote Egypt in their firstborn: for his mercy {endureth} for ever:

Exodus 12:12

For I will pass through the land of Egypt this night, and will smite all the firstborn in the land of Egypt, both man and beast; and against all the gods of Egypt I will execute judgment: I {am} the LORD. {gods: or, princes}

Exodus 11:4-5

And Moses said, Thus saith the LORD, About midnight will I go out into the midst of Egypt:

Exodus 4:23

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.

Psalms 135:8

Who smote the firstborn of Egypt, both of man and beast. {both...: Heb. from man unto beast}

Exodus 12:29-30

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. {dungeon: Heb. house of the pit}