This part of Mark’s gospel reads like a spy novel.
THE BAD GUYS
The religious establishment is plotting to murder Jesus. They liked things the way they used to be and did not care that God had a better way. Judas was their inside man. One of the closest to Jesus told the enemy where he could be found. He walked up to Jesus in the darkness and marked him for death with a kiss.
THE GOOD GUYS
Jesus' people are everywhere. Remember the ones who gave the Apostles the donkey colt? They heard the right phrase and provided Jesus' ride into Jerusalem. (Mark 11:1-6)
Jesus told the Apostles to look for a man carrying a pitcher of water. They would get the location for the evening's passover observance from him. This would have been an uncommon site, as getting of water was considered woman’s work but, in the hustle and bustle of passover, no one would have paid much attention to the man carrying water. On the other hand, for the Apostles, it was a secret sign.
God often works behind the scenes. Rahab was an innkeeper in the city of Jericho. She had heard about God and the miraculous delivery of His people from slavery in Egypt and decided to protect Israel's spies and advance God's agenda. (Joshua 2)
History is often remembered through the stories of kings and generals but God's story is told through faithful followers that are unimportant to the world.
THE SLEEPER AGENTS
There are infiltrators who live among us as normal people. They are loyal to another country and are ready to attack when orders are given. They have the capacity to do great damage because they act like everyone else; they talk the talk and walk the walk. Like Judas, they strike without warning.
One the other hand, even the schemes of the enemy can serve God's purposes. Judas was a key figure in the story of redemption. Joseph's brothers sold him into slavery but God used that event to save the people of Israel. The communist's expelled European missionaries from China but the church continued to grow.