Why is the Shabbat before Pesach called Shabbat Hagadol (The Great Shabbat)?
Often, the special Shabbatot are named after the beginning words of the Haftara as in the cases of Shabbat Chazon (Chazon Yishayahu), Shabbat Nachamu (Nachamu Nachamu Ami) and Shabbat Shuva (Shuva Yisrael). However, the beginning of the Haftara for Shabbat Hagadol (Malachi 3:4-24) does not have the word “gadol” in it. Rabbi Yisaschar Yaakovson points out that instead we find the word “gadol” near the end of the Haftara in sentence 23: “Behold! I will send you Eliyahu HaNavi (the prophet) before the great (gadol) and awesome day of God.”
The great day will come right before the final redemption.
What will Eliyahu do? In sentence 23 we read: “He shall restore the heart of the fathers to children and the heart of children to their fathers, lest I come and strike the land with destruction.”
The holiday of Pesach is the holiday of redemption so it makes sense to read the words about the final redemption while family members are getting ready to join together.
Why do we open the door on the seder night?
According to the Magen Avraham, by opening the door we are showing that we are not afraid. At the time of the Exodus, during the plague of Makat Bechorot (Firstborn) the doors were closed tight while the angel passed over the Jewish homes. Seder night is called “Leil Shimurim”, “Night of Watching” just as God protected the first born so too will he will protect us today and therefore we have nothing to fear.
The Talmud, Rosh HaShana 11a explains that the Jews are destined to be redeemed during the month of Nisan (the month of Pesach). Therefore we open the door in expectation of Eliyahu who will bring good news about the coming of the Mashiach.
The Maharal of Prague added a Prayer for Eliyahu to his seder. The prayer is a combination of what we say in Birkat HaMazon on a daily basis and the end of our Haftara:
HaRachaman hu yishlach lanu et Eliyahu HaNavi Zachur Latov, viyvaser lanu besorot tovot yeshuot venechamot kaamur hineh anochi sholeach lachem et Eliyahu HaNavi lifnei bo yom HaShem HaGadol VeHaNora, Veheshiv lev avot al banim vilev banim al avotam.
May the Merciful One send Eliyahu the prophet to announce good news about redemption and comfort- just as You promised: “Behold! I will send you Eliyahu HaNavi before the great and awesome day of God. He shall restore the heart of the fathers to children and the heart of children to their fathers.”
We learn from the story of the Exodus that there is always hope. Just as we were redeemed from slavery so too we shall once again be redeemed. When will that redemption come? When children and parents and those alienated from each other will get along.
The Maharal leaves out the words “lest I come and strike the land with destruction” and the Haftara ends on a positive note by repeating the words: “Behold! I will send you Eliyahu HaNavi before the great and awesome day of God” in the hope for a better future.