Numbers 18:15

Every thing that opens the womb in all flesh, which they bring unto the LORD, whether it be of men or animals, shall be yours: nevertheless the firstborn of man shall you surely redeem, and the firstling of unclean animals shall you redeem.

Exodus 34:20

But the firstling of a donkey you shall redeem with a lamb: and if you redeem it not, then shall you break its neck. All the firstborn of your sons you shall redeem. And none shall appear before me empty.

Exodus 13:2

Sanctify unto me all the firstborn, whatsoever opens the womb among the children of Israel, both of man and of beast: it is mine.

Exodus 13:12-13

That you shall set apart unto the LORD all that opens the womb, and every firstling that comes of a beast which you have; the males shall be the LORD'S.

Exodus 22:29

You shall not delay to offer the first of your ripe fruits, and of the outflow of your presses: the firstborn of your sons shall you give unto me.

Leviticus 27:26-27

Only the firstling of the animals, which should be the LORD'S firstling, no man may dedicate it; whether it be ox, or sheep: it is the LORD'S.

Numbers 3:13

Because all the firstborn are mine; for on the day that I struck all the firstborn in the land of Egypt I hallowed unto me all the firstborn in Israel, both man and animal: mine shall they be: I am the LORD.

Numbers 3:46

And for those that are to be redeemed of the two hundred and threescore and thirteen of the firstborn of the children of Israel, who are more than 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 you shall redeem with a lamb; and if you will not redeem it, then you shall break its neck: and all the firstborn of man among your children shall you redeem.
Exodus 34:20
But the firstling of a donkey you shall redeem with a lamb: and if you redeem it not, then shall you break its neck. All the firstborn of your sons you shall redeem. And none shall appear before me empty.
Leviticus 27:27
And if it be of an unclean animal, then he shall redeem it according to your valuation, and shall add a fifth part to it: or if it be not redeemed, then it shall be sold according to your valuation.

General references

Numbers 3:15
Number the children of Levi after the house of their fathers, by their families: every male from a month old and upward shall you number them.