Deuteronomy 16:1-3

MLV(i) 1 Observe the month of Abib and keep the Passover to Jehovah your God, for in the month of Abib Jehovah your God brought you forth out of Egypt by night. 2 And you will sacrifice the Passover to Jehovah your God, of the flock and the herd, in the place which Jehovah will choose to cause his name to dwell there.
3 You will eat no leavened bread with it. Seven days you will eat unleavened bread with it, even the bread of affliction, for you came forth out of the land of Egypt in haste, that you may remember the day when you came forth out of the land of Egypt all the days of your life.