Maimonides (Mishneh Torah, Laws of Hametz and Matza, Chapter 7) writes:

There is a positive mitzva (precept) in the Torah commanding us to relate all the wonders and miracles that happened to our forefathers in Egypt on the night of the 15th of Nisan. It is based on the verse: Remember this day that you left Egypt. (Exodus 13:3) The verse and you are to tell your son on that day (Exodus 13:8) teaches us that there is an obligation to relate the story of the Exodus specifically to children.

There are a considerable number of mitzvot that apply on this night: many obligations and many restrictions, rabbinical obligations and restrictions, details of laws, and customs that have become sanctified. Each mitzva should be observed at its correct time and in its correct sequence: neither too early, nor too late. Despite the destruction of the Temple, and the fact that we have neither the Pesach nor the Haggigah sacrifices, there are nonetheless still very many laws to observe on the Seder Night, and everyone should be careful in their observance of all the rabbinic laws connected with the Seder and the Haggadah.

Main themes connected with the Seder Night

1. The four main parts of the Seder Night :
   • Kiddush: kaddesh, rachatz, karpas, yachatz;
   • Narration: maggid;
   • Meal: rachatzah, motzi, matza, maror, korekh, shulkhan orekh, tzafun, barekh;
   • Conclusion of Hallel: hallel, nirtzah.
2. The Seder Plate:
   • Three matzot;
   • Shank bone, haroset, egg, maror, karpas.
3. The mitzvot of the evening:
   • Drinking four cups of wine;
   • Eating matza;
   • Eating maror;
   • Relating the story of the Exodus to the children;
4. Songs and hymns of praise.