TSK · Exodus 13:15

and I have said unto thee, Let my son go, that he may serve me; and thou hast refused to let him go: behold, I will slay thy son, thy first-born.

And the firstling of an ass thou shalt redeem with a lamb: and if thou wilt not redeem it, then thou shalt break its neck. All the first-born of thy sons thou shalt redeem. And none shall appear before me empty.