Also called Pesach, Passover is a major holy day celebrating the Israelites' exodus from Egypt and slavery. This holy day occurs on the 15th the Hebrew month Aviv in the spring. The Passover Seder, or the Feast of Unleavened Bread, is feast held on Passover night to begin the holy week. All leavened foods must be thrown out and Israelites do not eat anything with leaven for 7 days to remember their journey out of Egypt.