Exodus 12:15-17 Seven days shall you eat unleavened bread; even the first day you shall put away leaven out of your houses...
Exodus 13:6 Seven days you shall eat unleavened bread, and in the seventh day shall be a feast to the LORD.
Leviticus 23:6 And on the fifteenth day of the same month is the feast of unleavened bread to the LORD: seven days you must eat unleavened bread.