'First born' in the Bible

And thou shalt say to Pharaoh, Thus saith Jehovah: Israel is my son, my firstborn.

And I say to thee, Let my son go, that he may serve me. And if thou refuse to let him go, behold, I will kill thy son, thy firstborn.

These are the heads of their fathers' houses: the sons of Reuben, the firstborn of Israel: Enoch and Phallu, Hezron and Carmi: these are the families of Reuben.

And all the firstborn in the land of Egypt shall die, from the firstborn of Pharaoh who sitteth on his throne, even unto the firstborn of the bondwoman that is behind the mill; and all the firstborn of cattle.

And I will go through the land of Egypt in that night, and 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 Jehovah.

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

Hallow unto me every firstborn, whatever breaketh open the womb among the children of Israel, of man and of cattle: it is mine.

And every firstling of an ass shalt thou ransom with a lamb; and if thou do not ransom it, thou shalt break its neck; and every firstborn of a man among thy sons shalt thou ransom.

And it came to pass, when Pharaoh stubbornly refused to let us go, that Jehovah slew all the firstborn in the land of Egypt, both the firstborn of men and the firstborn of cattle: therefore I sacrifice to Jehovah all that breaketh open the womb being males; and every firstborn of my children I ransom.

Thou shalt not delay the fulness of thy threshing-floor and the outflow of thy winepress. The firstborn of thy sons shalt thou give unto me.

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