Exodus 34:20 in the King James Version
But the firstling of an ass thou shalt redeem with a lamb: and if thou redeem him not, then shalt thou break his neck. All the firstborn of thy sons thou shalt redeem. And none shall appear before me empty.
Context
19 “All that opens the womb is mine; and all your livestock that is male, the firstborn of cow and sheep.
20 You shall redeem the firstborn of a donkey with a lamb. If you will not redeem it, then you shall break its neck. You shall redeem all the firstborn of your sons. No one shall appear before me empty.
21 “Six days you shall work, but on the seventh day you shall rest: in plowing time and in harvest you shall rest.