Over the course of the seder, we drink the four cups of wine.  Why are there four cups of wine?  Each cup represents a phrase in the Torah (for the story of Pesach).  The four phrases are: והוצאתי, והצלתי, וגאלתי, ולקחתי (I will take you out, I will save you, I will redeem you, I will take you as a nation). 

All of the cups of wine represent redemption from slavery and that we are now royal.  At the seder, we usually lean to the left and drink the wine. We lean to the left to show that we, the Jews are kings and queens and no longer under the rule of Pharaoh. We drink these four cups of wine throughout the whole seder.  The first cup we drink is the kiddush at the start of the Seder, then closer to the end, after Birkat Hamazon and finally at the conclusion of Hallel.  At the seder, we have an obligation to drink four cups of wine. However, there is a fifth cup.  This cup we don’t drink, but we save it for Eliyahu Hanavi. 

There are many theories on why there are four cups of wine.  One talks about how the four cups represent the stages of Bnei Yisrael leaving Egypt and becoming their own nation.  The first cup represents the rescue from the harsh labor (this started when the plagues hit Egypt).  The second cup symbolizes when the Jews left Egypt, the third cup represents the splitting of the sea, when the Jews felt safe and the Egyptians came to capture them all.  Finally, the fourth cup symbolizes Bnei Yisrael becoming a nation at Har Sinai. 

(LINKS USED)

https://www.jewishvirtuallibrary.org/four-cups-of-wine-on-passover

https://www.chabad.org/holidays/passover/pesach_cdo/aid/658520/jewish/What-is-the-significance-of-the-four-cups.htm 50AoTqUK1zHlXkAWQ--WyuXLKYfiGFsajQtkeftucl18nRGGmzuZIoeMY4_ZYWmgO__cuRrLkcl1dLE_3S7u4SM6-S_IwYkgfes4hEltFqsAHPVDv_zeq6kW9Rl1hIRrH-bB-3CV


haggadah Section: Maggid - Beginning