Numbers 18:14-17

¹⁴Every devoted thing amongst the children of Israel shall be your.

¹⁵And every thing that opens the womb of all flesh, whatever they bring to the Lord, whether man or beast, shall be your: only the firstborn of men shall be surely redeemed, and you shall redeem the firstborn of unclean cattle.

¹⁶And the redemption of them shall be from a month old; their valuation of five shekels—it is twenty oboli according to the holy shekel.

¹⁷But you shall not redeem the firstborn of calves and the firstborn of sheep and the firstborn of goats; they are holy: and you shall pour their blood upon the altar, and you shall offer the fat as a burnt offering for a smell of sweet savour to the Lord.