'First born' in the Bible

He killed all the firstborn in Egypt,The first and best of their strength in the tents [of the land of the sons] of Ham.

“I will also make him My firstborn (preeminent),The highest of the kings of the earth.

He also struck down all the firstborn in their land,The first fruits and chief substance of all their strength.

Who struck the firstborn of Egypt,Both of man and animal;

To Him who struck the firstborn of Egypt,For His lovingkindness endures forever;