Halakhah zu Schemot 13:8

What does the evil [son] say? "'What is this worship to you?' (Exodus 12:26)" 'To you' and not 'to him.' And since he excluded himself from the collective, he denied a principle [of the Jewish faith]. And accordingly, you will blunt his teeth and say to him, "'For the sake of this did the Lord do [this] for me in my going out of Egypt' (Exodus 13:8)." 'For me' and not 'for him.' And if he had been there, he would not have been saved.

And [regarding] the one who doesn't know to ask, you will open [the conversation] for him. As it is stated (Exodus 13:8), "And you will speak to your son on that day saying, for the sake of this, did the Lord do [this] for me in my going out of Egypt." "And you will speak to your your son " - it could be from Rosh Chodesh [that one would have to discuss the Exodus. However] we learn [otherwise, since] it is stated, "on that day." If it is [written] "on that day," it could be from while it is still day [before the night of the fifteenth of Nissan. However] we learn [otherwise, since] it is stated, "for the sake of this." I didn't say [this] except [that it be observed] when [this] matsa and bitter herbs are resting in front of you [meaning, on the night of the fifteenth].

And in each and every generation, a person is obligated to show himself as if he left Egypt, as it is stated (Exodus 13:8); "For the sake of this, did the Lord do [this] for me in my going out of Egypt." Not only our ancestors did the Holy One, blessed be He, redeem, but rather also us [together] with them did He redeem, as it is stated (Deuteronomy 6:23); "And He took us out from there, in order to bring us in, to give us the land which He swore unto our fathers."