Numbers 18:15

Every firstborn male, human or animal that is brought to Jehovah is yours. But you must buy back every firstborn son and the firstborn male of any unclean animal.

Exodus 34:20

It will cost you a sheep or a goat to buy back the firstborn donkey. If you do not buy it back, then you must break the donkey's neck. You must buy back every firstborn of your sons. No one may come into my presence without an offering.

Exodus 13:2

Consecrate (appoint) (sanctify) all the first-born males to me. Every first-born male Israelite and every first-born male animal belongs to me!

Exodus 13:12-13

sacrifice every firstborn male offspring to Jehovah. The firstborn male offspring of each of your animals belongs to Jehovah.

Exodus 22:29

Do not delay the offering from your harvest and your vintage. Give the firstborn of your sons to me.

Leviticus 27:26-27

A firstborn animal already belongs to Jehovah because it was born first. Therefore, it cannot be set apart as holy. Whether it is a bull or a sheep, it belongs to Jehovah.

Numbers 3:13

because every firstborn is mine. The day I killed every firstborn male in Egypt, I set apart as holy every firstborn in Israel, whether human or animal. They will be mine. I am Jehovah.

Numbers 3:46

There are two hundred and seventy-three more firstborn male Israelites than there are 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
It will cost you a sheep or a goat to buy any firstborn donkey back from Jehovah. You must break the donkey's neck if you do not buy it back. You must also buy every firstborn son back from Jehovah.
Exodus 34:20
It will cost you a sheep or a goat to buy back the firstborn donkey. If you do not buy it back, then you must break the donkey's neck. You must buy back every firstborn of your sons. No one may come into my presence without an offering.
Leviticus 27:27
If it is an unclean animal it must be bought back. The payment will be its full value plus one-fifth more. If it is not bought back, it must be sold at the value given it.

General references

Numbers 3:15
Count the Levites by households and families. Count every male who is at least one month old.