Indeed, in the Book of Commandments (Sefer HaMitzvot) the Rambam wrote: "That we are commanded to recount the Exodus from Egypt on the night of the fifteenth of Nisan at the beginning of the night, according to the clarity of the recounting. And everything that is added in the narration, and if one elaborates on the greatness of what God did for us, and what the Egyptians did to us with harshness and cruelty, and how God took vengeance upon them for us, and in thanking Him for what He has bestowed upon us from His kindness, it will be even better. As they said (Haggadah of Passover), 'Whoever elaborates on recounting the Exodus from Egypt is praiseworthy.' And the scriptural basis for this command is the verse, 'You shall tell your child on that day, etc.' And the explanation is, 'You shall tell your child,' one might think from the beginning of the month, therefore it says, 'on that day.' If on that day, one might think from earlier in the day, therefore it says, 'for this.' Only when there is matzah and maror placed before you, meaning, from the beginning of the night you are obligated to recount."

It is clarified that the essence of the commandment is to recount the Exodus from Egypt and the kindness of the Almighty towards us and the vengeance He took on the Egyptians, but the recounting of the miracles and wonders that were done for our ancestors in Egypt is not included in this, and this is learned from the verse 'You shall tell your child.' And it requires clarification, for in the Book of the Hand (Sefer HaYad) it is written that the essence of the commandment is to recount the miracles and wonders that were done in Egypt.