There are many components of Jewish ritual life that involve food. The major dietary and religious laws applicable to food consumption, preparation and ritual in Judaism are set out in the Biblical Book of Leviticus and are considered part of Mosaic law.
One important ritual is the ceremony of Passover. This commemorates an event when the Israelites were captives in Egypt that is recounted in the Book of Exodus. God warned the Israelites that he intended to punish the Egyptians by killing their first born children. He instructed the Israelites to slaughter a perfect, unspotted lamb and mark the doorposts of their houses with the blood so that they would be "passed over" and their first born not slain. In their rush to escape Egypt after this night, they did not have time to let their bread rise, and thus during the festival, Jews still eat unleavened bread in remembrance.