Exodus 13:12-14

Young's Literal Translation

¹² that thou hast caused every one opening a womb to pass over to Jehovah, and every firstling -- the increase of beasts which thou hast: the males [are] Jehovah's.

¹³ `And every firstling of an ass thou dost ransom with a lamb, and if thou dost not ransom [it], then thou hast beheaded it: and every first-born of man among thy sons thou dost ransom.

¹⁴ `And it hath been, when thy son asketh thee hereafter, saying, What [is] this? that thou hast said unto him, By strength of hand hath Jehovah brought us out from Egypt, from a house of servants;