Exodus 13:6

‘Seven days you shall eat unleavened bread, but on the first day you shall remove leaven from your houses; for whoever eats anything leavened from the first day until the seventh day, that person shall be cut off from Israel.

“Six days you shall eat unleavened bread, and on the seventh day there shall be a solemn assembly to Yahweh your God; you shall do no work on it.

And the sons of Israel present in Jerusalem celebrated the Feast of Unleavened Bread for seven days with great gladness, and the Levites and the priests praised Yahweh day after day with loud instruments to Yahweh.