Exodus 34:20

And the first-born of an ass thou shalt redeem with a sheep, and if thou wilt not redeem it thou shalt pay a price: every first-born of thy sons shalt thou redeem: thou shalt not appear before me empty.

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.

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.