Read Matthew 22:15-20
15 The Pharisees went off and made a plan to trap Jesus with questions. 16Then they sent to him some of their disciples and some members of Herod’s party. “Teacher,” they said, “we know that you tell the truth. You teach the truth about God’s will for people, without worrying about what others think, because you pay no attention to anyone’s status. 17Tell us, then, what do you think? Is it against our Law to pay taxes to the Roman Emperor, or not?”
18 Jesus, however, was aware of their evil plan, and so he said, “You hypocrites! Why are you trying to trap me? 19Show me the coin for paying the tax!”
They brought him the coin, 20and he asked them, “Whose face and name are these?”
Jesus is asked about paying taxes. He plays a trick on the Pharisees - he asks them to show him a coin - and they produce one with the head of the emperor on it. Showing that they are willing to carry around a 'graven image' in their pockets.
Give to Caesar what is Caesars and to God what is God's reminds us that we are created in God's image - and we are to offer ourselves to God.