"Tell us, then, what is your opinion: Is it lawful to pay the census tax to Caesar or not?"
You don't have to be psychic or have divine knowledge to suspect that the disciples of the Pharisees along with the Herodians were up to no good. They attempt to butter up Jesus by claiming he teaches the way of God truthfully and puts no trust in people's opinion of him. Then they spring a trap—or so they thought. If Jesus answered yes, he was against the nationalistic dreams of the Jewish people. If he answered no, he would be in trouble with the Roman authorities.
Jesus calls them hypocrites, not just because they were attempting to trap him, but also because they were pretending to get along with each other in order to do so. The Pharisees and the Herodians were at opposite poles of the political spectrum—kind of like Democrats and Republicans today. The Pharisees hated Roman rule; the Herodians accepted it, and everything that went along with it including the census tax which was equal to a day's wage and had to be paid in Roman currency by every adult man, woman, and slave of the Jewish people.
Jesus asks for a coin. They produce a Roman coin, a bitter reminder of Roman rule and distasteful to most Jews. (What was it doing in their possession?) Jesus asks, "Whose image is this and whose inscription?" The image would be that of the present emperor and the wording would have been, "Tiberius Caesar, august son of the divine Augustus, high priest." Jesus responds: "Then repay to Caesar what belongs to Caesar."
Then Jesus adds a statement which should cause our jaws to drop: "...and to God what belongs to God." Think again about the question of whose image and whose inscription.
Aren't we created in God's image? Aren't we signed with the inscription of the cross at our baptism and every time we pray?
Each one of us belongs to God, minted as it were by God and for God. How then do we repay to God what belongs to God?
~Fr. Sas, October 19 Homily
29th Sunday in Ordinary Time, Year A