Which law do we serve?
Mark 12:13 And they send unto him certain of the Pharisees and of the Herodians, to catch him in his words.
They sent, the chief priests sent certain Pharisees, experts at the law and also liberal Herodians. Two opposites, the Pharisees supposedly teachers of God's law and the Herodians, the liberal politicians, sympathetic to Roman rule. Opposites joining together to attack Jesus with words, to try to cause him to break the law of God or the law of Rome. A two pronged attack.
Mark 12:14 And when they were come, they say unto him, Master, we know that thou art true, and carest for no man: for thou regardest not the person of men, but teachest the way of God in truth: Is it lawful to give tribute to Caesar, or not?
They begin by words of flattery, to gain a closer position of trust. Subtle they are, but what is their true intent? Jesus knew their hearts, he was not fooled by them.
Luke 12:1 In the mean time, when there were gathered together an innumerable multitude of people, insomuch that they trode one upon another, he began to say unto his disciples first of all, Beware ye of the leaven of the Pharisees, which is hypocrisy.
Luke 12:2 For there is nothing covered, that shall not be revealed; neither hid, that shall not be known.
...we know that thou art true, and carest for no man: for thou regardest not the person of men, but teachest the way of God in truth: Is it lawful to give tribute to Caesar, or not?
After the flattering praise, they come up with the question to trick him.
Mark 12:15 Shall we give, or shall we not give? But he, knowing their hypocrisy, said unto them, Why tempt ye me? bring me a penny, that I may see it.
Shall we give tribute to Caesar? If he said no, one would be offended. For one was of God's law, the other of Roman laws. If he said yes, the Jews hated the tribute money and would not like that answer. Bring a Roman coin to him.
Mark 12:16 And they brought it. And he saith unto them, Whose is this image and superscription? And they said unto him, Caesar's.
Mark 12:17 And Jesus answering said unto them, Render to Caesar the things that are Caesar's, and to God the things that are God's. And they marvelled at him.
They marveled and so do we at his wisdom. We owe to God, His things and to the government, their things. We obey laws, unless they are laws prohibiting the free worship of God. Even so, no man can stop the heart from worshipping God and doing good.
The greatest struggle of obeying God is in the mind.
Rom 7:21 I find then a law, that, when I would do good, evil is present with me.
Rom 7:22 For I delight in the law of God after the inward man:
Rom 7:23 But I see another law in my members, warring against the law of my mind, and bringing me into captivity to the law of sin which is in my members.
Rom 7:24 O wretched man that I am! who shall deliver me from the body of this death?
Rom 7:25 I thank God through Jesus Christ our Lord. So then with the mind I myself serve the law of God; but with the flesh the law of sin.
Rom 8:1 There is therefore now no condemnation to them which are in Christ Jesus, who walk not after the flesh, but after the Spirit.
Rom 8:2 For the law of the Spirit of life in Christ Jesus hath made me free from the law of sin and death.
Obey that which is good and lawful from your heart.