The Passover was a great annual event.  It was an evening meal which was followed by the Feast of Unleavened Bread - a whole week of celebration commemorating God's deliverance of His people from slavery in Egypt (Exodus 12:17).  Leaven (another word for yeast) made bread rise but made it susceptible to going bad if not eaten soon after baking.  In the Exodus from Egypt, the bread for the journey needed to last until God provided Manna, the bread from heaven.  Leaven was also a symbol for sin … a little bit will corrupt the whole loaf (1 Corinthians 5:6).  Before the Feast of Unleavened Bread, all traces of yeast had to be removed from the house.  Jesus, our Passover Lamb, had no sin but died for our sins.

Yet a wicked conspiracy was going on between rebellious human hearts and Satan's malignant desire to exterminate the Prince of Life.  The religious leaders, who should have welcomed Jesus, hated Him intensely.  They envied His real power and authority (Matthew 27:18; Mark 1:22).  He had exposed their corruption and hypocrisy and they felt threatened by someone so pure and powerful.  So they wanted to kill Him (Luke 19:47).  

But there was a problem: all the people thought Jesus was wonderful, and, if the religious hierarchy was seen to be against Jesus, they risked being toppled from their positions of power (John 11:48).  But their evil thoughts were all part of Satan's plan.  He had been grooming the weakest of the twelve disciples, Judas Iscariot, encouraging him to steal from the money given to Jesus (John 12:6).  Now the time had come, and Satan entered into Judas' heart and mind, taking control of man and precipitating a cascade of actions which would lead Jesus to the cross, and Judas to unrepentant remorse and fatal self-loathing (Acts 1:18).

It is always a bad idea to rebel against God, to use Him for personal gain, or in any way to collaborate with the devil.  Most people do not think that their selfish rebellion is anything more than getting their own way, which they try to justify.  However, it potentially opens a door to far greater evil than was ever anticipated at first.  Although we know from the end of this story that God used all the wickedness to achieve the salvation of the world, those who participated in it came to a shameful end.  The destructive desire of Satan only needs a little human collaboration to produce terrible consequences.  That is why Peter says, "Be alert and of sober mind. Your enemy the devil prowls around like a roaring lion looking for someone to devour. Resist him, standing firm in the faith ..." (1 Peter 5:8-9).  It is time to review your heart's desires: if they are not in tune with the Lord's will, repent quickly before Satan takes advantage.