'First born' in the Bible

And thither thou shalt come, and thither ye shall bring your burnt sacrifices and your offerings, your tithes and heave offerings of your hands, your vows and free will offerings and thy first born of your oxen and of your sheep.

Thou mayest not eat within thy gates the tithe of thy corn, of thy wine and of thy oil, either the firstborn of thine oxen or of thy sheep, neither any of thy vows which thou vowest, nor thy freewill offerings or heave offerings of thine hands:

And thou shalt eat before the LORD thy God, in the place which he hath chosen to make his name dwell there, the tithe of thy corn, of thy wine and of thine oil, and the firstborn of thine oxen and of thy flock that thou mayest learn to fear the LORD thy God always.

All the firstborn that come of thine oxen and of thy sheep that are males, thou shalt hallow unto the LORD thy God. Thou shalt do no service with the firstborn of thy sheep:

if the firstborn be the son of the hated: then when he dealeth his goods among his children, he may not make the son of the beloved firstborn before the son of the hated which is indeed the firstborn:

But he shall know the son of the hated for his firstborn, that he give him double of all that he hath. For he is the first of his strength, and to him belongeth the right of the firstbornship.

His beauty is as a firstborn ox and his horns as the horns of an unicorn. And with them he shall push the nations together, even unto the ends of the world. These are the many thousands of Ephraim and the thousands of Manasseh."