Exodus 12:14,24 And this day shall be to you for a memorial; and you shall keep it a feast to the LORD throughout your generations...
Exodus 23:15 You shall keep the feast of unleavened bread: (you shall eat unleavened bread seven days, as I commanded you...
Leviticus 23:6 And on the fifteenth day of the same month is the feast of unleavened bread to the LORD: seven days you must eat unleavened bread.
Deuteronomy 16:3,4 You shall eat no leavened bread with it; seven days shall you eat unleavened bread therewith, even the bread of affliction...