The Passover meal commemorated a special event in the history of Israel, reminding them of their deliverance from Egypt, but along with the meal of that night, the Lord wanted them to continue to do something for the next seven days,
“You shall eat no leavened bread with it; seven days you shall eat unleavened bread with it, that is, the bread of affliction (for you came out of the land of Egypt in haste), that you may remember the day in which you came out of the land of Egypt all the days of your life. And no leaven shall be seen among you in all your territory for seven days, nor shall any of the meat which you sacrifice the first day at twilight remain overnight until morning” (Deuteronomy 16.3, 4).
Not eating leavened bread for seven days reminded them perfectly of the experience of leaving Egypt in haste, preventing them from allowing their to bread to raise, because they had to leave while Pharaoh’s order still stood, lest he change his mind and decide not to let Israel go!
They kept moving for seven days, and so they were unable to make bread as they normally would have done.
The Lord always does things perfectly, and wants us to do them perfectly to the best of our ability and with His grace making up the difference!