Numbers 18:15

Everything that opens the womb, of all flesh which they offer to Yahweh, both of man and animal shall be yours: nevertheless you shall surely redeem the firstborn of man, and you shall redeem the firstborn of unclean animals.

Exodus 34:20

The firstborn of a donkey you shall redeem with a lamb: and if you will not redeem it, then you shall break its neck. All the firstborn of your sons you shall redeem. No one shall appear before me empty.

Exodus 13:2

"Sanctify to me all of the firstborn, whatever opens the womb among the children of Israel, both of man and of animal. It is mine."

Exodus 13:12-13

that you shall set apart to Yahweh all that opens the womb, and every firstborn which you have that comes from an animal. The males shall be Yahweh's.

Exodus 22:29

"You shall not delay to offer from your harvest and from the outflow of your presses. "You shall give the firstborn of your sons to me.

Leviticus 27:26-27

"'Only the firstborn among animals, which is made a firstborn to Yahweh, no man may dedicate it; whether an ox or sheep, it is Yahweh's.

Numbers 3:13

for all the firstborn are mine. On the day that I struck down all the firstborn in the land of Egypt I made holy to me all the firstborn in Israel, both man and animal. They shall be mine. I am Yahweh."

Numbers 3:46

For the redemption of the two hundred seventy-three of the firstborn of the children of Israel, who exceed 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
Every firstborn of a donkey you shall redeem with a lamb; and if you will not redeem it, then you shall break its neck; and you shall redeem all the firstborn of man among your sons.
Exodus 34:20
The firstborn of a donkey you shall redeem with a lamb: and if you will not redeem it, then you shall break its neck. All the firstborn of your sons you shall redeem. No one shall appear before me empty.
Leviticus 27:27
If it is an unclean animal, then he shall buy it back according to your valuation, and shall add to it the fifth part of it: or if it isn't redeemed, then it shall be sold according to your valuation.

General references

Numbers 3:15
"Count the children of Levi by their fathers' houses, by their families. You shall count every male from a month old and upward."