Numbers 18:17-18

¹⁷“But you shall not redeem the firstborn of a cow, or the firstborn of a sheep, or the firstborn of a goat. They are holy. You shall sprinkle their blood on the altar, and shall burn their fat for an offering made by fire, for a pleasant aroma to Yahweh.

¹⁸Their meat shall be yours, as the wave offering breast and as the right thigh, it shall be yours.