'First born' in the Bible

And thou shalt say unto Pharaoh, Thus saith Jehovah, Israel is my son, my first-born:

and I have said unto thee, Let my son go, that he may serve me; and thou hast refused to let him go: behold, I will slay thy son, thy first-born.

These are the heads of their fathers houses. The sons of Reuben the first-born of Israel: Hanoch, and Pallu, Hezron, and Carmi; these are the families of Reuben.

and all the first-born in the land of Egypt shall die, from the first-born of Pharaoh that sitteth upon his throne, even unto the first-born of the maid-servant that is behind the mill; and all the first-born of cattle.

For I will go through the land of Egypt in that night, and will smite all the first-born in the land of Egypt, both man and beast; and against all the gods of Egypt I will execute judgments: I am Jehovah.

And it came to pass at midnight, that Jehovah smote all the first-born in the land of Egypt, from the first-born of Pharaoh that sat on his throne unto the first-born of the captive that was in the dungeon; and all the first-born of cattle.

Sanctify unto me all the first-born, whatsoever openeth the womb among the children of Israel, both of man and of beast: it is mine.

And every firstling of an ass thou shalt redeem with a lamb; and if thou wilt not redeem it, then thou shalt break its neck: and all the first-born of man among thy sons shalt thou redeem.

and it came to pass, when Pharaoh would hardly let us go, that Jehovah slew all the first-born in the land of Egypt, both the first-born of man, and the first-born of beast: therefore I sacrifice to Jehovah all that openeth the womb, being males; but all the first-born of my sons I redeem.

Thou shalt not delay to offer of thy harvest, and of the outflow of thy presses. The first-born of thy sons shalt thou give unto me.

And the firstling of an ass thou shalt redeem with a lamb: and if thou wilt not redeem it, then thou shalt break its neck. All the first-born of thy sons thou shalt redeem. And none shall appear before me empty.