LOS ANGELES, Calif.—Passover, which celebrates what the Old Testament describes as God's deliverance of the Israelites from bondage in Egypt, begins at sundown today with observant Jews in the Southland and around the world gathering for a feast called a Seder.

Seders feature six symbolic foods, including matzo, a cracker-like unleavened bread symbolizing the Exodus from the land of pharaoh, when there was not enough time to let the bread rise. Jews are not supposed to eat anything leavened during the holiday period.

Bitter herbs, often horseradish, represent the bitterness of slavery in Egypt; parsley dipped in saltwater symbolizes the tears the Israelites would have shed in bondage; and an apple, nut, spice and wine mixture called charoset represents what the Old Testament describes as the mortar used by Jewish slaves to build Egyptian edifices.

According to the book of Exodus, enslaved Israelites used the blood of lambs to mark their doors so the Angel of Death would "pass over'' their homes and instead slay the firstborn sons of Egyptians—the 10th and most horrific plague that finally persuaded the pharaoh to agree to Moses' demand: "Let my people go.''

During the Seder, people drink four cups of wine or grape juice. As part of the ritual, a child traditionally asks "the four questions,'' the first being, "Why is this night different from all other nights?''

The meal is accompanied by reading from the Haggadah, or "narration'' book, which tells the story of the Israelites' deliverance from bondage.

Passover is observed for seven days in Israel and eight days by many outside Israel because of different interpretations of Jewish law. Outside Israel, Seders are held on the first two days of Passover.

In his Passover message, President Barack Obama wrote that the story of Passover "inspires hope that those oppressed and enslaved can become free.''

"The Seder, with its rich traditions and rituals, instructs each generation to remember its past, while appreciating the beauty of freedom and the responsibility it entails,'' Obama wrote.

"This year, that ancient instruction is reflected in the daily headlines as we see modern stories of social transformation and liberation unfolding in the Middle East and North Africa.

"Against the backdrop of change, we continue to pray for peace between Israel and her neighbors, while reaffirming our enduring commitment to Israel's security,'' Obama wrote.