"The chief priests and scribes were looking for a way to arrest Jesus by stealth and kill him; for they said, "Not during the festival, or there may be a riot among the people."
Now, who do you think the chief priests and scribes were afraid of? As I have read this narrative, it being so familiar to me, I've said to myself, "well obviously they are afraid of the people; that they will turn violent, and the lives of the chief priests and scribes will be in danger."
Ah, but remember that it is the Festival of Unleavened Bread. The remembrance of the Passover and the Israelites Exodus from Egypt. The streets of Jerusalem are alive with excitement, energy, and a sense of hope. Maybe this year, God will restore them fully to their promised land and remove their oppressors from power. Knowing this is a real possiblity, the Romans would have stocked the streets with soliders. The Governor, Pilate, came to town to see that nothing happened. Soldiers with itchy trigger fingers, or knife hands, as they case may be, are ready to quell any protest. A riot this week, is most certianly a bad thing. Not only would the Chief Priests and the Scribes be in danger from the people, but their whole way of being, the comfy, cozy relationship they've setup with their Roman oppressors would have fallen apart. I riot means the thumb of Rome coming down on them, and that they can't afford.
So they find a way to arrest Jesus by stealth; by the betrayal of one of his own.
It never ceases to amaze me how a familiar story can have all sorts of deeper meaning when time and care are taken to read the details that fall between the lines.