'First born' in the Bible

and there you shall bring your burnt offerings, and your sacrifices, and your tithes, and the wave offering of your hand, and your vows, and your freewill offerings, and the firstborn of your herd and of your flock:

You may not eat within your gates the tithe of your grain, or of your new wine, or of your oil, or the firstborn of your herd or of your flock, nor any of your vows which you vow, nor your freewill offerings, nor the wave offering of your hand;

You shall eat before Yahweh your God, in the place which he shall choose, to cause his name to dwell there, the tithe of your grain, of your new wine, and of your oil, and the firstborn of your herd and of your flock; that you may learn to fear Yahweh your God always.

All the firstborn males that are born of your herd and of your flock you shall sanctify to Yahweh your God: you shall do no work with the firstborn of your herd, nor shear the firstborn of your flock.

If a man have two wives, the one beloved, and the other hated, and they have borne him children, both the beloved and the hated; and if the firstborn son be hers who was hated;

then it shall be, in the day that he causes his sons to inherit that which he has, that he may not make the son of the beloved the firstborn before the son of the hated, who is the firstborn:

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

It shall be, that the firstborn whom she bears shall succeed in the name of his brother who is dead, that his name not be blotted out of Israel.

The firstborn of his herd, majesty is his. His horns are the horns of the wild ox. With them he shall push the peoples all of them, [even] the ends of the earth: They are the ten thousands of Ephraim. They are the thousands of Manasseh."