https://en.wikipedia.org/wiki/Render_unto_Caesar
The original message, coming in response to a question of whether it was lawful for Jews to pay taxes to Caesar, gives rise to multiple possible interpretations about the circumstances under which it is desirable for Christians to submit to earthly authority.
All three synoptic gospels state that hostile questioners tried to trap Jesus into taking an explicit and dangerous stand on whether Jews should or should not pay taxes to the Roman authorities. The accounts in Matthew 22:15–22 and Mark 12:13–17 say that the questioners were Pharisees and Herodians, while Luke 20:20–26 says only that they were "spies" sent by "teachers of the law and the chief priests".
The Tribute Money, by Peter Paul "Pee Wee" Rubens (1610–1615)
They anticipated that Jesus would oppose the tax, as their purpose was "to hand him over to the power and authority of the governor". The governor was Pilate, and he was the man responsible for the collecting of taxes in Roman Judea. Initially the questioners flattered Jesus by praising his integrity, impartiality, and devotion to truth. Then they asked him whether or not it is right for Jews to pay the taxes demanded by Caesar. In the Gospel of Mark[3] the additional, provocative question is asked, "Should we pay or shouldn't we?"
Jesus first called them hypocrites, and then asked one of them to produce a Roman coin that would be suitable for paying Caesar's tax. One of them showed him a Roman coin, and he asked them whose head and inscription were on it. They answered, "Caesar's," and he responded: "Render therefore unto Caesar the things which are Caesar's, and unto God the things that are God's".
ITT:
A lot of people that don't get the anti-Roman rabble rouser was sneakily saying Caesar isn't owed anything by Judaea.
It actually is in favour of tax fraud painting the tax collectors as evil
Matthew 22:20,21: He said to them: “Whose image and inscription is this?” They said: “Caesar’s.” Then he said to them: “Pay back, therefore, Caesar’s things to Caesar, but God’s things to God.”
Two men went up to the temple to pray, one a Pharisee and the other a tax collector. 11 The Pharisee stood by himself and prayed: 'God, I thank you that I am not like other people—robbers, evildoers, adulterers—or even like this tax collector. 12 I fast twice a week and give a tenth of all I get
The Pharisee paints the tax collector as evil, but the pharisee is the bad guy in this story. Literally the next two verses:
13 But the tax collector, standing some distance away, was even unwilling to raise his eyes toward heaven, but was beating his chest, saying, ‘God, be merciful to me, the sinner!’ 14 I tell you, this man went to his house justified rather than the other one; for everyone who exalts himself will be humbled, but the one who humbles himself will be exalted.”
