What does Matthew 22:18 mean?

The Pharisees were trying to set Jesus up. They have sent their own disciples, along with some from a group known as the Herodians, to spring a trap. The attempt began with flattery, then sprang what was meant to look like a dispute between those two groups. Their assumption is that Jesus will either claim paying taxes to Rome is part of the law, alienating His followers, or that it should not be paid, subjecting Him to prosecution as a rebel (Matthew 22:15–17).

Jesus, though, is never fooled, not even by a question this loaded. He knows they have approached Him with insincerity; in fact, this question is being asked out of "malice," translated from the Greek root term poneros, which can also mean "wickedness or evil." They pretend to be believers; in truth, they are trying to hurt Him. The English term "malice" implies a prejudicial intent to cause another person harm.

Jesus calls them out for the attempted deception, rightly calling them hypocrites. This is an especially apt term in this case, since the Greek term hypokritēs literally refers to an "actor." These challengers are only pretending to respect Christ's teaching. Their pretense is an outright lie for the purpose of getting Him arrested and killed.

And yet, Jesus does not neglect to give some answer to the issue. His response (Matthew 22:19–21) distinguishes between the secular and spiritual worlds and implies a deeper need for believers to commit themselves to God.