Exodus 13:10

Therefore, you shall keep this ordinance at its appointed time from year to year.

Exodus 12:14

‘Now this day will be a memorial to you, and you shall celebrate it as a feast to the Lord; throughout your generations you are to celebrate it as a permanent ordinance.

Exodus 12:24-25

And you shall observe this event as an ordinance for you and your children forever.

Exodus 23:15

You shall observe the Feast of Unleavened Bread; for seven days you are to eat unleavened bread, as I commanded you, at the appointed time in the month Abib, for in it you came out of Egypt. And none shall appear before Me empty-handed.

Leviticus 23:6

Then on the fifteenth day of the same month there is the Feast of Unleavened Bread to the Lord; for seven days you shall eat unleavened bread.

Deuteronomy 16:3-4

You shall not eat leavened bread with it; seven days you shall eat with it unleavened bread, the bread of affliction (for you came out of the land of Egypt in haste), so that you may remember all the days of your life the day when you came out of the land of Egypt.

Treasury of Scripture Knowledge

Summary

Thou shalt therefore keep this ordinance in his season from year to year.

Bible References

General references

Exodus 12:14
‘Now this day will be a memorial to you, and you shall celebrate it as a feast to the Lord; throughout your generations you are to celebrate it as a permanent ordinance.
Exodus 23:15
You shall observe the Feast of Unleavened Bread; for seven days you are to eat unleavened bread, as I commanded you, at the appointed time in the month Abib, for in it you came out of Egypt. And none shall appear before Me empty-handed.
Leviticus 23:6
Then on the fifteenth day of the same month there is the Feast of Unleavened Bread to the Lord; for seven days you shall eat unleavened bread.
Deuteronomy 16:3
You shall not eat leavened bread with it; seven days you shall eat with it unleavened bread, the bread of affliction (for you came out of the land of Egypt in haste), so that you may remember all the days of your life the day when you came out of the land of Egypt.