The Obligations of the Holiday explain the Pesach, Matzah, and Maror.  However, we have not answered all of the Four Questions and we have not explained all of the items on the Seder Plate or explained why we drink four cups of wine.  Here are the answers and explanations.

Answers to the Four Questions

1) On all other nights we eat chametz or matzah, on this night only matzah!
Slavery: Matzah was the bread of slaves and poor, it was cheap to produce and easy to make.
Freedom: Matzah also commemorates the fact that the bread did not have enough time to rise when the Jews hastily left Egypt.
2) On all other nights we eat any kind of herbs and vegetables, on this night only bitter herbs!
Slavery: The maror (bitter herbs) reminds us of the bitterness of slavery in Egypt.
3) On all other nights we do not dip even once, on this night we do so twice!
Slavery: The salt water into which we dip the karpas and egg represents the tears we cried while in Egypt.
Freedom: Dipping food is considered a luxury; a sign of freedom — as opposed to the poor (and enslaved) who eat "dry" and un-dipped foods.
4) On all nights we eat sitting upright or reclining, and on this night we all recline!
Freedom: We commemorate our freedom by reclining on cushions like royalty.
 
Seder Plate

Z'roah (Roasted Bone): A roasted lamb bone is placed on the Seder plate symbolizing the Paschal sacrifice (Korban Pesach) that was offered during the Temple period in Jerusalem. It was traditionally roasted and eaten as part of the meal on Seder night, The Z'roah is not eaten or handled during the Seder. 

Beitzah (Egg): A roasted, hard-boiled egg represents the holiday sacrifice (Korban Chaggigah) that was offered on every holiday, including Passover, during the Temple period in Jerusalem. The egg also symbolizes mourning, representing our sadness over the destruction of the Holy Temple, while at the same time it is a symbol of springtime fertility.  Because of its round shape, the egg represents the cycle of life, reminding us that even in the most difficult times, there is always hope for renewal.  The Beitzah is not eaten or handled at the Seder.  Some families have a tradition of eating hard-boiled eggs dipped in salt water before the meal or just prior to the Four Questions. 

Maror (Bitter Herbs) and Hazeret: The bitter herbs remind us of the bitterness of the slavery endured by the Israelites in Egypt. Sliced or grated horseradish and/or romaine lettuce/celery are used interchangeably. Not everyone agrees on the need for both, but many Seder plates have a place for Hazeret, since the commandment in the Bible for eating Maror is written in the plural. 

Charoset: This sweet mixture represents the mortar used by the enslaved Israelites to make bricks to build the Pharaoh's cities and palaces. Ashkenazic Charoset is traditionally made by mixing together grated apples, sweet red wine, cinnamon, and chopped nuts. Sephardic Charoset often included dates and honey instead of apples. 

Karpas (Green Vegetable): The Karpas is dipped in salt water, in the Ashkenazic tradition, or vinegar, in the Sephardic tradition, before being eaten to commemorate the tears, pain, and sadness felt by the Israelites while enslaved in Egypt. The Karpas, usually parsley, also represents the early years of prosperity in Egypt, as well as symbolizing spring and renewal. It is dipped in salt water and eaten directly after the Kiddush.

Four Cups of Wine

In Genesis 40:11-13, when Joseph interprets the dream of the butler, the butler mentions the word "cup" four times. The  Midrash  suggests that these cups alluded to the liberation of the Israelites from Pharaoh's rule

Then there is God's promise to take the Israelites out of Egyptian slavery in Exodus 6:6-8, in which there were four terms used to describe the redemption:

  1. I shall take you out ...
  2. I shall rescue you ...
  3. I shall redeem you ... 
  4. I shall bring you ... 

There are four evil decrees by Pharaoh that the Israelites were liberated from, including:

  1. Slavery
  2. The murder of all newborn males
  3. The drowning of all Israelite boys in the Nile 
  4. The order for the Israelites to collect their own straw to make bricks

Another opinion cites the four exiles that the Israelites suffered and the freedom that was (or will be) granted from each, including:

  1. The Egyptian exile
  2. The Babylonian exile
  3. The Greek exile
  4. The current exile and the coming of the Messiah

There's a reason provided, also, that in the  Haggadah  Jews read about the forefathers Abraham, Isaac, Jacob, and Esau, and Jacob's son Yosef, but the matriarchs do not appear in the narrative. This view suggests that because of this, each cup of wine represents one of the matriarchs: Sarah, Rebekah, Rachel, and Leah

The Cup of Elijah is the fifth cup that appears at the seder.


haggadah Section: -- Cup #2 & Dayenu