In the traditional Passover seder, participants will consume four cups of wine. There are several reasons for this specific number, most of which are symbolic. For example, the number four is significant in part because the words "cup of wine" are mentioned four times during a prophetic passage in the story of Exodus, which details the Jewish people's escape from Egyptian slavery.
Other justifications for the specific consumption of four cups of wine include the fact that Jewish slaves were liberated from four decrees made by the Egyptian pharaoh. Additionally, it can be said that the cups represent the four instances of exile that Jewish people have experienced throughout history.