Leviticus 23:5—6, “The Passover to the LORD begins at twilight on the fourteenth day of the first month. On the fifteenth day of the same month begins the Feast of Unleavened Bread to the LORD. For seven days you must eat unleavened bread.” Passover is an event that really only lasts as long as it takes to eat a meal. The Feast of Unleavened Bread is the actual feast that would last for the seven day period. Today however most people think of Passover as the week long feast.