Numbers 18:15

All [the] first offspring of a womb of any creature that they offer to Yahweh, whether human or animal, will be yours; you will surely redeem the firstborn of the human and the unclean firstborn of the animal.

Exodus 34:20

But the first offspring of a donkey you will redeem with small livestock, and if you will not redeem [it], you will break its neck. Every firstborn of your sons you will redeem, and you will not appear before me empty-handed.

Exodus 13:2

"Consecrate to me every firstborn, the first offspring of every womb among the {Israelites}, among humans and among domestic animals; {it belongs to me}."

Exodus 13:12-13

you will hand over every first offspring of a womb to Yahweh, and every first offspring dropped by a domestic animal that will belong to you, the males [will be] for Yahweh.

Exodus 22:29

" 'You will not delay the fullness of your harvest and the juice from your press; you will give me the firstborn of your sons.

Leviticus 27:26-27

" 'However, a man shall not consecrate a firstborn among livestock, which belongs as firstborn to Yahweh; whether an ox {or} small livestock, it is for Yahweh.

Numbers 3:13

because all [the] firstborn [are] mine; on the day of my killing all [the] firstborn in the land of Egypt, I consecrated for myself all [the] firstborn in Israel, {both humankind and animal}; they will be mine. I am Yahweh."

Numbers 3:46

And the ransom of the two hundred and seventy-three of the firstborn of the {Israelites} who are excessive over 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 first offspring of a donkey you will redeem with small livestock, and if you will not redeem [it], then you will break its neck, and every firstborn human among your sons you will redeem.
Exodus 34:20
But the first offspring of a donkey you will redeem with small livestock, and if you will not redeem [it], you will break its neck. Every firstborn of your sons you will redeem, and you will not appear before me empty-handed.
Leviticus 27:27
And if [it is] among the unclean animals, then he shall ransom [it] according to your proper value, and he shall add a fifth of its [value] onto it; and if it is not redeemed, then it shall be sold according to your proper value.

General references

Numbers 3:15
"Muster the descendants of Levi according to {their families}, according to their clans. You will count every male from {one month} and above."