Because all the firstborn are mine; for on the day that I smote all the firstborn in the land of Egypt I hallowed unto me all the firstborn in Israel, both man and beast: mine shall they be: I am Yahweh.
Also the firstborn of our sons, and of our cattle, as it is written in the law, and the firstlings of our herds and of our flocks, to bring to the house of our Elohim, unto the priests that minister in the house of our Elohim:
That thou shalt set apart unto Yahweh all that first opens the womb, and every firstling that cometh of a beast which thou hast; the males shall be Yahweh's.
And it came to pass, when Pharaoh would hardly let us go, that Yahweh slew all the firstborn in the land of Egypt, both the firstborn of man, and the firstborn of beast: therefore I sacrifice to Yahweh all males that first open the womb; but all the firstborn of my children I redeem.
And the first of all the firstfruits of all things, and every oblation of all, of every sort of your oblations, shall be the priest's: ye shall also give unto the priest the first of your dough, that he may cause the blessing to rest in thine house.
Every thing that openeth the matrix in all flesh, which they bring unto Yahweh, whether it be of men or beasts, shall be thine: nevertheless the firstborn of man shalt thou surely redeem, and the firstling of unclean beasts shalt thou redeem.
And I, behold, I have taken your brethren the Levites from among the children of Israel: to you they are given as a gift for Yahweh, to do the service of the tabernacle of the congregation.
And thou shalt take the Levites for me I am Yahweh instead of all the firstborn among the children of Israel; and the cattle of the Levites instead of all the firstlings among the cattle of the children of Israel.
To the general assembly and assembly of the firstborn, which are written in heaven, and to Yahweh the Judge of all, and to the spirits of just men made perfect,