Exodus 12:14, 24
And this day will be a memorial for you, and you are to celebrate it as a feast to the LORD, as a lasting ordinance for the generations to come. . . .

Exodus 23:15
You are to observe the Feast of Unleavened Bread as I commanded you: At the appointed time in the month of Abib you are to eat unleavened bread for seven days, because that was the month you came out of Egypt. No one may appear before Me empty-handed.

Leviticus 23:6
On the fifteenth day of the same month begins the Feast of Unleavened Bread to the LORD. For seven days you must eat unleavened bread.

Deuteronomy 16:3, 4
You must not eat leavened bread with it; for seven days you are to eat with it unleavened bread, the bread of affliction, because you left the land of Egypt in haste--so that you may remember for the rest of your life the day you left the land of Egypt. . . .