Numbers 18:15

Everything that opens the womb, of all flesh which they offer to LORD, both of man and beast shall be thine. Nevertheless the first-born of man thou shall surely redeem, and the firstling of unclean beasts thou shall redeem.

Exodus 34:20

And the firstling of a donkey thou shall redeem with a lamb, and if thou will not redeem it, then thou shall break its neck. All the first-born of thy sons thou shall redeem. And none shall appear before me empty.

Exodus 13:2

Sanctify to me all the first-born, whatever opens the womb among the sons of Israel. Both of man and of beast, it is mine.

Exodus 13:12-13

that thou shall set apart to LORD all that opens the womb. And every firstling which thou have that comes of a beast, the males shall be LORD's.

Exodus 22:29

Thou shall not delay to offer from thy harvest, and from the outflow of thy presses. The first-born of thy sons thou shall give to me.

Leviticus 27:26-27

Only the firstling among beasts, which is made a firstling to LORD, no man shall sanctify it, whether it be ox or sheep, it is LORD's.

Numbers 3:13

for all the first-born are mine. On the day that I smote all the first-born in the land of Egypt I hallowed to me all the first-born in Israel, both man and beast. They shall be mine. I am LORD.

Numbers 3:46

And for the redemption of the two hundred and seventy-three of the first-born of the sons of Israel, who are over and above [the number of] the Levites,

Treasury of Scripture Knowledge

Summary

Every thing that openeth the matrix in all flesh, which they bring unto the LORD, 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.

General references

Bible References

The firstborn

Exodus 13:13
And every firstling of a donkey thou shall redeem with a lamb, and if thou will not redeem it, then thou shall break its neck. And all the first-born of man among thy sons thou shall redeem.
Exodus 34:20
And the firstling of a donkey thou shall redeem with a lamb, and if thou will not redeem it, then thou shall break its neck. All the first-born of thy sons thou shall redeem. And none shall appear before me empty.
Leviticus 27:27
And if it be of an unclean beast, then he shall ransom it according to thine estimation, and shall add to it the fifth part of it, or if it be not redeemed, then it shall be sold according to thy estimation.

General references

Numbers 3:15
Number the sons of Levi by their fathers' houses, by their families. Thou shall number them, every male from a month old and upward.