Exodus 13:11-13

And after the LORD brings you into the land of the Canaanites and gives it to you, as He swore to you and your fathers,

you are to present to the LORD the firstborn male of every womb. All the firstborn males of your livestock belong to the LORD.

You must redeem every firstborn donkey with a lamb, and if you do not redeem it, you are to break its neck. And every firstborn of your sons you must redeem.