Passover is an important day for the Christian and Jewish faiths, but it is not a holy day established by God. Passover will be forever linked to a holy day; it was a day to get ready for slaughtering the lamb just before sunset and paint its blood on the doorposts. The Angel of Death went through Egypt during that night, so the Passover lamb had to be killed just before sunset in order for the Israelites to be safely in their homes, covered by its blood. After that they roasted the kid and ate it that evening, it was a night to be much remembered. Biblical days begin at sunset, so the Passover meal would be eaten on the first of the two annual holy day Sabbaths of Unleavened Bread. 

Exodus 12:8..10-16 King James Version
8 And they shall eat the flesh in that night, roast with fire, and unleavened bread; and with bitter herbs they shall eat it…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. 

1 Corinthians 5:6 Amplified Bible
6 Your boasting [over the supposed spirituality of your church] is not good [indeed, it is vulgar and inappropriate]. Do you not know that [just] a little leaven ferments the whole batch [of dough, just as a little sin corrupts a person or an entire church]?

In commemorating this event the Israelites were to eat no leavened food or have leaven on their property. Getting leaven out of their lives, can symbolize Christians getting sin out of theirs. Do you keep any Israelite traditions?