'First born' in the Bible

Then shalt thou say unto Pharaoh, Thus, saith Yahweh - My son - my firstborn, is Israel;

Therefore I say unto thee, Let my son go, that he may serve me, But if thou refuse to let him go, behold, I, am going to slay, thy son, thy firstborn.

These, are the heads of their ancestral house: The sons of Reuben the first-born of Israel, Hanoch and Pallu, Hezron and Carmi. These are the families of, Reuben.

then shall every firstborn in the land of Egypt die, from the firstborn of Pharaoh who is sitting on his throne, unto the firstborn of the handmaid who is behind the two millstones, - and every firstborn of beasts;

I will pass along, therefore, throughout the land of Egypt this night, and will smite every firstborn in the land of Egypt, from man even to beast, - and against all the gods of Egypt, will I execute judgments - I, Yahweh.

And it came to pass, at midnight, that Yahweh, smote every firstborn in the land of Egypt, from the firstborn of Pharaoh who sat upon his throne, unto the firstborn of the captive who was in the pit of his prison, - and every firstborn of beasts.

Hallow to me every firstborn, that which any female first beareth among the sons of Israel, among men and among beasts, - mine! it is.

But every firstling of an ass, shalt thou redeem with a lamb or if thou wilt not redeem it, then thou shalt break its neck, - but every firstborn of men among thy sons, shalt thou redeem.

And it came to pass when Pharaoh had shown himself too hardened to let us go, then did Yahweh slay every firstborn in the land of Egypt, from the firstborn of men even unto the firstborn of beasts. For this cause, am, I, sacrificing to Yahweh whatsoever is born first, of the males, and every firstborn of my sons, must I redeem.

Thy fulness and thine outflow, shalt thou not delay, - the firstborn of thy sons, shalt thou give to me.

But the firstling of an ass, thou mayst redeem with a lamb, and if thou wilt not redeem it, then shalt thou break its neck. Every firstborn of thy sons, shalt thou redeem, and he must not see my face, with empty hand.