Exodus 13:7, 20-22

Unleavened bread shall be eaten throughout the seven days; and there shall no leavened bread be seen with thee, neither shall there be leaven seen with thee, in all thy borders.

And they took their journey from Succoth, and encamped in Etham, in the edge of the wilderness. And Jehovah went before them by day in a pillar of cloud, to lead them the way, and by night in a pillar of fire, to give them light; that they might go by day and by night: the pillar of cloud by day, and the pillar of fire by night, departed not from before the people.