This line is from Matthew 22: 15-21 and similarly in Mark 12: 13-17.
The Pharisees are once again trying to trip up Jesus. Accompanied by Herod sympathizers, they say to Jesus, “Is it lawful to pay tax to the emperor or not?”
Jesus knows they ask the question in bad faith. “Why are you trying to trip me up, you hypocrites?” he asks. “Show me the coin used for the tax.” They show him a Roman coin and he asks whose face is on the coin. They respond that it is Caesar. Jesus instructs, “Then give to Caesar what is Caesar’s, but give to God what is God’s.”
The Pharisees and Herod sympathizers are taken aback and leave.
Likely everyone has heard of this story. I recommend you read the whole scripture; I have shortened it slightly, though the message is the same regardless: Sometimes we are required to give in to the secular world as it demands while we live according to God’s world in our personal lives.
A good example of this today is the case of the county clerk in Kentucky who believes that same-sex marriage is against God’s will and refuses to issue marriage licenses, even though the U.S. Supreme Court has declared that same-sex marriages are legal in all 50 states. The governor of Kentucky has instructed all county clerks to begin issuing marriage licenses as is their duty, yet the country clerk Kim Davis still refuses to issue them claiming her faith demands it. When asked by whose authority she refuses to issue the licenses, Ms Davis replies, “God’s authority.” She has been jailed for contempt of court.
But by Jesus’ direction in this reading, it would seem that God’s authority is to issue the licenses, giving to Caesar what is Caesar’s, absolving Ms Davis of any sin because in her heart she is personally giving to God what is God’s.
Sometimes we go overboard in reading into God’s intentions. Jesus gives us a way to meet our societal obligations while remaining true to our faith. In the case of the Kentucky county clerk who has a sworn duty to issue marriage licenses to everyone, Jesus tells her she can meet her professional obligations without missing her obligations to God.