Exodus 13:6

For seven days you shall eat unleavened bread, and on the seventh day there shall be a feast to the Lord.

Exodus 12:15-20

[In the celebration of the Passover in future years,] seven days you shall eat unleavened bread, but on the first day you shall remove the leaven from your houses [because it represents the spread of sin]; for whoever eats leavened bread on the first day through the seventh day, that person shall be cut off and excluded from [the atonement made for] Israel.

Exodus 34:18

“You shall observe the Feast of Unleavened Bread (Passover). For seven days you shall eat unleavened bread, as I have commanded you, at the appointed time in the month of Abib; for in the month of Abib you came out of Egypt.

Leviticus 23:8

But you shall present an offering by fire to the Lord for seven days; on the seventh day there shall be a holy convocation; you shall not do any laborious work [on that day].’”

Treasury of Scripture Knowledge did not add