'Ordinance Forever' in the Bible

‘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.

You shall also observe the Feast of Unleavened Bread, because on this very day I brought your hosts [grouped according to tribal armies] out of the land of Egypt; therefore you shall observe this day throughout your generations as an ordinance forever.