Exodus 12:14-16

‘Now this day will be a memorial to you, and you shall keep it as a feast to the LORD; throughout your generations you are to celebrate it as an ordinance forever. [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. On the first day [of the feast] you shall have a holy and solemn assembly, and on the seventh day there shall be another holy and solemn assembly; no work of any kind shall be done on those days, except for the preparation of food which every person must eat—only that may be done by you.