Exodus 12:24-27

24And ye shall observe this as an ordinance for thee and for thy sons for ever.

25And it shall come to pass, when ye are come into the land that Jehovah will give you, as he has promised, that ye shall keep this service.

26And it shall come to pass, when your children shall say to you, What mean ye by this service?

27that ye shall say, It is a sacrifice of passover to Jehovah, who passed over the houses of the children of Israel in Egypt when he smote the Egyptians and delivered our houses. And the people bowed their heads and worshipped.