Exodus 12:17

So you are to keep the Feast of Unleavened Bread, for on this very day I brought your divisions out of the land of Egypt. You must keep this day as a permanent statute for the generations to come.

Note That is, the seven-day period after the Passover during which no leaven may be eaten

And ye shall observe the feast of unleavened bread; for in this selfsame day have I brought your armies out of the land of Egypt: therefore shall ye observe this day in your generations by an ordinance for ever.

You shall observe the feast of unleavened bread; for in this same day I have brought your armies out of the land of Egypt. Therefore you shall observe this day throughout your generations by an ordinance forever.

And ye shall observe the feast of unleavened bread; for in this selfsame day have I brought your hosts out of the land of Egypt: therefore shall ye observe this day throughout your generations by an ordinance for ever.