Numbers 18:15-17

Amplified Bible, Classic Edition

¹⁵ Everything that first opens the womb in all flesh, which they bring to the Lord, whether it be of men or beasts, shall be yours. Nevertheless the firstborn of man you shall surely redeem, and the firstling of unclean beasts you shall redeem.

¹⁶ And those that are to be redeemed of them, from a month old shall you redeem, according to your estimate [of their age], for the fixed price of five shekels in silver, according to the shekel of the sanctuary, which is twenty gerahs.

¹⁷ But the firstling of a cow or of a sheep or of a goat you shall not redeem. They [as the firstborn of clean beasts belong to God and] are holy. You shall sprinkle their blood upon the altar and shall burn their fat for an offering made by fire, for a sweet and soothing odor to the Lord.