Exodus 12:15
15 vSeven days you shall eat unleavened bread. On the first day you shall remove leaven out of your houses, for if anyone eats what is leavened, from the first day until the seventh day, wthat person shall be cut off from Israel.
Exodus 13:6
6 xSeven days you shall eat unleavened bread, and on the seventh day there shall be a feast to the Lord.
2 Chronicles 30:21
21 And the people of Israel who were present at Jerusalem kept cthe Feast of Unleavened Bread seven days with great gladness, and the Levites and the priests praised the Lord day by day, singing with all their might1 to the Lord.
2 Chronicles 35:17
17 And the people of Israel who were present kept the Passover at that time, cand the Feast of Unleavened Bread seven days.