I pray this opens up some understanding for you and blesses your life in some way!
Exodus 12:8-21
[8] And they shall eat the flesh in that night, roast with fire, and unleavened bread; and with bitter herbs they shall eat it.
[9] Eat not of it raw, nor sodden at all with water, but roast with fire; his head with his legs, and with the purtenance thereof.
[10] And ye shall let nothing of it remain until the morning; and that which remaineth of it until the morning ye shall burn with fire.
[11] And thus shall ye eat it; with your loins girded, your shoes on your feet, and your staff in your hand; and ye shall eat it in haste: it is the LORD’s passover.
[12] For I will pass through the land of Egypt this night, and will smite all the firstborn in the land of Egypt, both man and beast; and against all the gods of Egypt I will execute judgment: I am the LORD.
[13] And the blood shall be to you for a token upon the houses where ye are: and when I see the blood, I will pass over you, and the plague shall not be upon you to destroy you, when I smite the land of Egypt.
[14] And this day shall be unto you for a memorial; and ye shall keep it a feast to the LORD throughout your generations; ye shall keep it a feast by an ordinance for ever.
[15] Seven days shall ye eat unleavened bread; even the first day ye shall put away leaven out of your houses: for whosoever eateth leavened bread from the first day until the seventh day, that soul shall be cut off from Israel.
[16] And in the first day there shall be an holy convocation, and in the seventh day there shall be an holy convocation to you; no manner of work shall be done in them, save that which every man must eat, that only may be done of you.
[17] 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.
[18] In the first month, on the fourteenth day of the month at even, ye shall eat unleavened bread, until the one and twentieth day of the month at even.
[19] Seven days shall there be no leaven found in your houses: for whosoever eateth that which is leavened, even that soul shall be cut off from the congregation of Israel, whether he be a stranger, or born in the land.
[20] Ye shall eat nothing leavened; in all your habitations shall ye eat unleavened bread.
[21] Then Moses called for all the elders of Israel, and said unto them, Draw out and take you a lamb according to your families, and kill the passover.
To answer this question, consider the leavening in bread as the way that sin affects our lives. It was and is observed to eat to remember the 430 years of captivity to Pharaoh (and sin).
What does leaving do? It puffs up bread! A little leavening added to a mixture of bread goes a long way when it comes to how much it will expand the substance of it. When we compare that to temptations it becomes very clear that it does not take very much of a temptation to something before it becomes something that causes a decline (puffs up) our spiritual lives. To say that you are consuming unleavened bread not only says you are observing the salvation and deliverance that you have but is also a token to the commitment that we take as Christians to live holy (or separate) lives before God.
There is also another significance to the unleavened philosophy! When you consider Jesus in the moments of the passover, He referred to the bread He broke as His body (or the sacrifice with the flesh being broken). This should be a very implicit picture of the integrity that goes behind that bread. It should remind us whether we are observing passover or just living everyday life that living a Holy life is done by living a separate life from sin. In that commitment is able to be made possible by the sacrifice of Jesus Christ!