What does Luke 20:20 mean?
Jesus has told a parable which local religious leaders rightly interpret as a warning directed at themselves: He is the Son of God and if they kill Him, God will destroy them. They become so angry that they try harder to kill Him. A major problem for these spiteful leaders is that Jesus is immensely popular with the common people; the leaders crave the crowd's adoration, not their anger (Luke 20:9–19).Since Jesus came, the religious leaders have had to work harder to maintain the goodwill of the people. They can't compete against miracles of healing and meals for thousands of people. Just recently Jesus raised Lazarus from the dead (John 11:43–45). Their scheme not only requires killing Jesus, but it also means taking out Lazarus as well (John 12:9–11).
The topics at hand are power and authority. The leaders want to trick Jesus into either disenfranchising the people or breaking a law which would result in arrest by the Romans. Jesus recently cleared the temple court (Luke 19:45–46); the religious leaders don't like that, but when they tried to challenge Jesus' authority, He threatened their standing with the crowd (Luke 20:1–8).
The leaders try again. The only way they see to destroy Jesus without dirtying their hands is to trick Him into breaking the Roman law. During Jesus' earthly ministry, the people and lands of Judea are under occupation by the Romans. Even though Jews have received special permission to worship their own God, they still need to pay the census tax. The assumption behind their impending trick (Luke 20:22) is that Jesus must choose one of two bad options: to endorse Rome, thereby alienating the Jews, or to speak against the occupiers, thereby being viewed as an enemy of Rome.
The scribes are from the Pharisee sect and they send in their disciples as spies. Herodians who have been conspiring with the Pharisees to destroy Jesus since the beginning of His ministry also join in (Matthew 22:15–16; Mark 3:6). The priests are mostly Sadducees. The only popular sects not mentioned are the zealots, who want to conquer the Romans with violence, and the Essenes, semi-mystics who generally stick to the desert.
First the Pharisees (Luke 20:19–26) and then the Sadducees (Luke 20:27–40) discover Jesus can't be tricked. The priests later try to find people willing to falsely accuse Him (Mark 14:55–56). When the "witnesses" can't agree, their last resort is coercing the Roman governor to execute Jesus by threatening accusations of treason (John 19:12–16).