Numbers 18:16-18

American Standard Version

^16 [a]And those that are to be redeemed of them from a month old shalt thou redeem, according to thine estimation, for the money of five shekels, after the shekel of the sanctuary (the same is twenty gerahs). ¹⁷ But the firstling of a cow, or the firstling of a sheep, or the firstling of a goat, thou shalt not redeem; they are holy: thou shalt sprinkle their blood upon the altar, and shalt burn their fat for an offering made by fire, for a sweet savor unto Jehovah. ¹⁸ And the flesh of them shall be thine, as the wave-breast and as the right thigh, it shall be thine.