The story of Jesus commanding us to give unto Caesar that which is Caesar’s is commonly misrepresented as His commanding us to give to Caesar the denari which he asks for (i.e., to pay taxes to government), as—it is assumed—the denari are Caesar’s, being that they have Caesar’s image and name on them. But Jesus never said that this was so! What Jesus did say though was an ingenious case of rhetorical misdirection to avoid being immediately arrested, which would have interfered with Old Testament prophecy of His betrayal as well as His own previous predictions of betrayal.
When the Pharisees asked Jesus whether or not it is lawful to pay taxes to Caesar, they did so as a ruse in the hopes of being able to either have Him arrested as a rebel by the Roman authorities or to have Him discredited in the eyes of His followers. At this time in Israel’s history it was an occupied territory of the Roman Empire, and taxes—which were being used to support this occupation—were much-hated by the mass of the common Jews. Thus, this question was a clever Catch-22 posed to Jesus by the Pharisees: if Jesus answered that it is not lawful then the Pharisees would have Him put away, but if He answered that it is lawful then He would appear to be supporting the subjection of the Jewish people by a foreign power. Luke 20:20 makes the Pharisees’ intent in asking this question quite clear:
So they watched Him, and sent spies who pretended to be righteous, that they might seize on His words, in order to deliver Him to the power and the authority of the governor.
Thus, Jesus was not free to answer in just any casual manner. Of the Scripture prophecies which would have gone unfulfilled had He answered that it was fine to decline paying taxes and been arrested because of it are the betrayal by Judas and Jesus’s betrayer replaced. Here is a quote from Peter on this matter from Acts 1:16: