Matthew 22:15-22 (New International Version)
Then the Pharisees went out and laid plans to trap him [Jesus] in his words. They sent their disciples to him along with the Herodians. "Teacher," they said, "we know you are a man of integrity and that you teach the way of God in accordance with the truth. You aren't swayed by men, because you pay no attention to who they are. Tell us then, what is your opinion? Is it right to pay taxes to Caesar or not?"
Then he said to them, "Give to Caesar what is Caesar's, and to God what is God's."
When they heard this, they were amazed. So they left him and went away.
Source: Bible Gateway.com