Exodus 13:12 in the King James Version
That thou shalt set apart unto the LORD all that openeth the matrix, and every firstling that cometh of a beast which thou hast; the males shall be the LORD’s.
Context
11 “It shall be, when the LORD brings you into the land of the Canaanite, as he swore to you and to your fathers, and will give it to you,
12 that you shall set apart to the LORD all that opens the womb, and every firstborn that comes from an animal which you have. The males shall be the LORD’s.
13 Every firstborn of a donkey you shall redeem with a lamb; and if you will not redeem it, then you shall break its neck; and you shall redeem all the firstborn of man among your sons.