Exodus 12:24-27

24And you shall observe this thing as an ordinance for you and your sons forever.

25It will come to pass when you come to the land which the Lord will give you, just as He promised, that you shall keep this service.

26And it shall be, when your children say to you, ‘What do you mean by this service?’

27that you shall say, ‘It is the Passover sacrifice of the Lord, who passed over the houses of the children of Israel in Egypt when He struck the Egyptians and delivered our households.’ ” So the people bowed their heads and worshiped.