Numbers 18:15
King James Version
“Every thing that openeth the matrix in all flesh, which they bring unto the LORD, 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.”
Context
12All the best of the oil, and all the best of the wine, and of the wheat, the firstfruits of them which they shall offer unto the LORD, them have I given thee.
13whatsoever is first ripe in the land, which they shall bring unto the LORD, shall be thine; every one that is clean in thine house shall eat it.
14Every thing devoted in Israel shall be thine.
15Every thing that openeth the matrix in all flesh, which they bring unto the LORD, 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.
16And those that are to be redeemed from a month old shalt thou redeem, according to thine estimation, for the money of five shekels, after the shekel of the sanctuary, which twenty gerahs.
17But the firstling of a cow, or the firstling of a sheep, or the firstling of a goat, thou shalt not redeem; they holy: thou shalt sprinkle their blood upon the altar, and shalt burn their fat an offering made by fire, for a sweet savour unto the LORD.
18And the flesh of them shall be thine, as the wave breast and as the right shoulder are thine.