What is the significance of the word "va'Amartem"?
Pesachim 116b: It is from here that the Ba'al Hagadah learns the obligation to give reasons for Pesach, Matzah and Maror, 1 to the point that if one has not, he has not fulfilled his obligation. 2
Pesachim 116b: The Pesach - Because Ha'Kadosh-Baruch-Hu passed over the houses of our fathers in Egypt - as cited in the current Pasuk. Matzah - Because our fathers were redeemed from Egypt, as the Torah writes, " And they baked the dough... Matzah cakes... " (12:39). Maror - Because the Egyptians embittered the lives of our fathers in Egypt (Shemos 1:14).
See Torah Temimah, note 203.
What are the implications of "Zevach Pesach Hu"?
Rashi (to Pesachim 59b): "Zevach Pesach" teaches us that the Korban Pesach must be Shechted 1 for the sake of the Pesach; and "Pesach Hu' teaches that if it is not, it is Pasul even b'Di'eved.
Pesachim 97a: It implies 'Hu Pesach, 2 v'Ein Temuraso Pesach' - to teach us that the Temuras Pesach 3 before Pesach is not brought as a Shelamim (like a Temuras Pesach after Pesach).
Yerushalmi Pesachim, 5:2: Following the Pasuk in Re'eh, "v'Asisa Pesach La'Shem Elokecha"(Devarim 16:1) (implying that all of its Avodos must be performed for the sake of the Pesach), "Zevach Pesach Hu" teaches us that this is restricted to Avodos that, like 'Zevichah' (Shechitah), are crucial to the Avodah -- but not to burning the Eivarim and Eimurim, which is not.
Why did the Ba'al Hagadah change the answer to the wicked son's statement, from that of the Torah?
Oznayim la'Torah: Because, whereas the Torah is speaking about sons who have forgotten the Torah, 1 the Ba'al Hagadah explains the question according to the other explanation of the Mechilta. 2
Torah Temimah, note 203: 'The Torah is not giving an answer to the Rasha, 3 but is rather presenting an independent Mitzvah regarding the Seder.'
Why did the people prostrate themselves?
Rashi: On the good news that they had just received - the Redemption and their coming to Eretz Yisrael, and the children that they would have. 1
Tosfos ha'Shalem (7, citing R. Efrayim): They thanked Hashem that the Resha'im were buried during the plague of darkness, so the Egyptians did not notice that also Yisrael were afflicted. 2
Mechilta: Because they heard about the miracles that Hashem would perform in Egypt. This teaches us that whoever hears about these miracles, should praise Him. 3
See Sifsei Chachamim.,
Tosfos ha'Shalem (ibid.): This teaches us that if one's enemies are unaware of one's suffering, he should rejoice.
Mechilta: And so the Pasuk states, "And Yisro declared, 'Blessed be Hashem Who saved you from the hand of Egypt!" (18:10). See also Torah Temimah, note 209.
QUESTIONS ON RASHI
Rashi writes that one of the reasons they bowed down was the good news that they will have children. They heard about a wicked son!
Tosfos ha'Shalem (10): Moshe saw that they were pained about the wicked children, so he said, 'Tell them "Zevach Pesach Hu... v'Es Bateinu Hitzil," meaning that they will repent.'
Tosfos ha'Shalem (8) #1: They did not realize that Moshe was referring to a wicked son.
Tosfos ha'Shalem (8): #2: One must thank Hashem for bad tidings just like for good. 1
