Numbers 18:15

Every firstborn of the womb of all flesh, whether it is man or animal, which they bring to the Lord, shall be yours; nevertheless, the firstborn of man you shall most certainly redeem, and the firstborn of unclean animals you shall redeem.

Exodus 34:20

You shall redeem the firstborn of a donkey with a lamb; but if you do not redeem it, then you shall break its neck. You shall redeem all the firstborn of your sons. None of you are to appear before Me empty-handed.

Exodus 13:2

“Sanctify to Me [that is, set apart for My purpose] every firstborn, the first offspring of every womb among the children of Israel, both of man and of animal; it is Mine.”

Exodus 13:12-13

you shall set apart and dedicate to the Lord all that first opens the womb. All the firstborn males of your livestock shall be the Lord’s.

Exodus 22:29

“You shall not delay the offering from your harvest and your vintage. You shall give (consecrate, dedicate) to Me the firstborn of your sons.

Leviticus 27:26-27

‘However, the firstborn among animals, which as a firstborn belongs to the Lord, no man may consecrate, whether an ox or a sheep. It is [already] the Lord’s.

Numbers 3:13

for all the firstborn are Mine. On the day that I killed all the firstborn in the land of Egypt, I consecrated for Myself all the firstborn in Israel, both man and animal. They shall be mine; I am the Lord.”

Numbers 3:46

For the ransom (redemption price) of the 273 of the firstborn of the Israelites who outnumber 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 by [substituting] a lamb [as a sacrifice for it], but if you do not [wish to] redeem it, then you shall break its neck; and every firstborn among your sons you shall redeem [that is, “buy back” from God with a suitable sacrifice].
Exodus 34:20
You shall redeem the firstborn of a donkey with a lamb; but if you do not redeem it, then you shall break its neck. You shall redeem all the firstborn of your sons. None of you are to appear before Me empty-handed.
Leviticus 27:27
If it is among the unclean animals, the owner may redeem it in accordance with your valuation, and add one-fifth to it; or if it is not redeemed, then it shall be sold in accordance with your valuation.

General references

Numbers 3:15
“Number the sons of Levi by their fathers’ households, by their families (clans). You shall number every male from a month old and upward.”