Exodus 13:13

Overview - Exodus 13
The firstborn are sanctified to God.
The memorial of the passover is commanded.
11 The firstlings of man and beast are set apart.
17 The Israelites go out of Egypt, and carry Joseph's bones with them.
20 They come to Etham.
21 God guides them by a pillar of a cloud, and a pillar of fire.
Treasury of Scripture Knowledge

Exodus 13:13  (King James Version)
And every firstling of an ass thou shalt redeem with a lamb; and if thou wilt not redeem it, then thou shalt break his neck: and all the firstborn of man among thy children shalt thou redeem.

of an ass
34:20 Numbers 18:15-17

or, kid.
Exodus 12:3 Exodus 12:21

shalt thou
Numbers 3:46-51 ; Numbers 18:15 Numbers 18:16 Revelation 14:4