Exodus 13:11-14

13:11 When the Lord brings you into the land of the Canaanites, as he swore to you and to your fathers, and gives it to you, 13:12 then you must give over to the Lord the first offspring of every womb. Every firstling of a beast that you have – the males will be the Lord’s. 13:13 Every firstling of a donkey you must redeem with a lamb, and if you do not redeem it, then you must break its neck. Every firstborn of your sons you must redeem.

13:14 In the future, when your son asks you ‘What is this?’ you are to tell him, ‘With a mighty hand the Lord brought us out from Egypt, from the land of slavery.