The narrative of the plagues is interspersed with educative points which were highlighted and explained in the Haggadah with its commentaries. For example, the story of the tenth plague, the slaying of the first-born, is connected by the sacrifice of the lamb, and the smearing of the blood on the door-post, to the command ”You should observe this matter as a decree for yourself and for your children forever. And when you come to the land which G-d will give you, you should observe this service. And when your children say to you, “what is this service to you?” you should answer them saying, “ It is a pesach feast offering to G-d, who passed over the houses of the children of Israel, in Egypt, when he smote the Egyptians but saved our houses”.
This is used as part of the dialogue of the Four sons in the Haggadah, but it uses the questions and answers in a different order from the order in the parasha. The recollection of the deliverance from Egypt is expressed through discourse and through ritual. On all occasions, G-d asks Jewish parents to bring their children, to inspire them with the knowledge of G-d’s ways. This will ensure the continuity of the nation.
Nechama Leibowitz devoted a commentary to the expression “ it is because of this, which the Lord did for me when I left Egypt”. She quoted Ramban who said that the “this” referred to the miracles which G-d performed at the time. Ibn Ezra took the “this” to refer maintained that the Exodus was staged by G-d for the sake of “this” – for the observing his precepts, starting with those of Pesach. Rashi specified three Pesach observances, pesach sacrifice, matza and maror, and Ibn Ezra added the removal of chametz, “the first precepts ordained for us by G-d”. Leibowitz concluded that “this”, though referring to the actual rites mentioned in the immediate context, symbolises all our religious obligations, all the precepts of Judaism.