Exodus 13:10
see thou keep therefore this ordinance in his season from year to year.
Exodus 12:14
And this day shall be unto you a remembrance, and ye shall keep it holy unto the LORD: even throughout your generations after you shall ye keep it holy day, that it be a custom forever.
Exodus 12:24-25
Therefore see that thou observe this thing, that it be an ordinance to thee, and thy sons forever.
Exodus 23:15
Thou shalt keep the feast of sweet bread, that thou eat unleavened bread seven days long as I commanded thee in the time appointed of the month of Abib, for in that month thou camest out of Egypt: and see that no man appear before me empty.
Leviticus 23:6
And the fifteenth day of the same month is the feast of sweet bread unto the LORD; seven days ye must eat unleavened bread.
Deuteronomy 16:3-4
Thou shalt eat no leavened bread therewith: but shalt eat therewith the bread of tribulation seven days long. For thou camest out of the land of Egypt in haste, that thou mayest remember the day when thou camest out of the land of Egypt, all days of thy life.