
Passover, an eight-day long holiday, begins on the 15th of Nissan in the Jewish calendar. It celebrates the exodus of the entire nation of Israel from Egypt after hundreds of years of slavery there, about 3300 years ago. Shortly after leaving Egypt, the Jews received the Torah, both written and Oral, at Mt. Sinai. The Torah includes G-d’s commandments for the Jewish people. Many of these commandments apply specifically to the celebration of Passover. One of the Mitzvot of the Seder night is to drink four cups of wine. One might ask how the drinking of wine on Passover is in any way associated to the holiday and what the reasons are for having such a commandment.
The quantity “four” tends to reappear in several times during the celebration of Passover as, in addition to four cups of wine, there are also four questions asked and the passage describing the four sons is read. This indicates that the number four is significant to Passover. Different rabbis have offered different ideas on the importance of the number. One reason is that the four cups of wine stand for the four stages of redemption that G-d stated he would carry out, as well as fulfilled. These were: “I shall take you out”, “I shall rescue you”, “I shall redeem you” and “I shall take you to me”. So we drink four cups of wine to commemorate the four expressions of our freedom from slavery.
Another reason given is that the four cups are to remember our four foremothers. However, the foremothers Sarah, Rivkah, Rachel and Leah lived several generations before the time of the Exodus and even before slavery in Egypt. So why would they be significant to Passover? The answer is that they each played an important part in the formation of the nation of Israel, and each cup of wine has a specific purpose during the Seder meal, which is associated with one of the foremothers. The purpose of the first cup of wine is to recite the Kiddush, where it talks about the holiness of the nation of Israel, and Sarah was known to celebrate Shabbat, the holy day. The second cup is drunk after reading about the establishment of the nation of Israel, about Abraham being an idol-worshipper and coming to believe in one G-d. Rivkah, born into a family of idol-worshippers, was able to accept one G-d and help shape the beginnings of the nation of Israel. After finishing our meal and saying Birkat HaMazon to thank G-d for our food, we drink the third cup to remember Rachel, mother of Joseph, who helped to ensure there would be food during years of famine in Egypt. The fourth and final cup is to remember Leah who taught the nation of Israel about saying thank-you when she thanked G-d for the birth of her fourth son, Yehudah. The fourth cup comes right after reciting the Hallel, where we say thank-you to G-d for being taken out of Egypt. So this Passover when you drink your four cups of wine, remember that they’re a reminder of what G-d did for the Jewish people.
http://www.wzo.org.il/en/resources/view.asp?id=195
http://www.torah.org/learning/yomtov/pesach/5757/vol3no02.html