The eight-day festival of Passover is celebrated in the early spring, from the 15th through the 22nd of the Hebrew month of Nissan. Passover (Pesach) commemorates the emancipation of the Israelites from slavery in ancient Egypt. Pesach is observed by avoiding leaven, and highlighted by the Seder meals that include four cups of wine, eating matzah and bitter herbs, and retelling the story of the Exodus.