'First born' in the Bible

You are to bring there your burnt offerings and sacrifices, your tenths and personal contributions, your vow offerings and freewill offerings, and the firstborn of your herds and flocks.

Within your gates you may not eat: the tenth of your grain, new wine, or oil; the firstborn of your herd or flock; any of your vow offerings that you pledge; your freewill offerings; or your personal contributions.

You are to eat a tenth of your grain, new wine, and oil, and the firstborn of your herd and flock, in the presence of Yahweh your God at the place where He chooses to have His name dwell, so that you will always learn to fear the Lord your God.

“You must consecrate to the Lord your God every firstborn male produced by your herd and flock. You are not to put the firstborn of your oxen to work or shear the firstborn of your flock.

If a man have two wives, one beloved, and another hated, and they have born him children, both the beloved and the hated; and if the firstborn son be hers that was hated:

Then it shall be, when he maketh his sons to inherit that which he hath, that he may not make the son of the beloved firstborn before the son of the hated, which is indeed the firstborn:

But he shall acknowledge the son of the hated for the firstborn, by giving him a double portion of all that he hath: for he is the beginning of his strength; the right of the firstborn is his.

And it shall be, that the firstborn which she beareth shall succeed in the name of his brother which is dead, that his name be not put out of Israel.

His firstborn bull has splendor,and horns like those of a wild ox;he gores all the peoples with themto the ends of the earth.Such are the ten thousands of Ephraim,and such are the thousands of Manasseh.