Jesus famously said "Render unto Caesar what belongs to Caesar". I'll argue that he meant 23 Deadly Stab Wounds — and yet that he wasn't advocating violence.
A Jew preaching to Jews, Jesus had been publicly challenged by enemies to tell whether his religious views demand that Jews should pay the exacting taxes levied by the Roman occupation army, universally hated by all Jews for its violence and cruelty. This was putting him in a double bind: either say yes and be denounced to all Jews as an accomplice of the tyrannical oppressors; or say no, and be denounced to Romans as preaching rebellion and face execution.
Jesus very cleverly escapes the double bind by having his challenger produce a coin minted with the face of Caesar and replying that thou shalt render unto Caesar what belongs to Caesar, and to God what belongs to God. A great answer that demands neither subjection to the Romans nor rebellion against them, but instead demands that his followers should understand the importance of Justice, the importance of Force, and the importance of the difference between the two.
What Jesus clearly doesn't possibly mean is that Caesar is a good guy: every single Jew in Judea where Jesus was speaking knew that Caesar is a tyrant who owes his power to mass murder. By that time, "Caesar" was a title worn by Tiberius, successor of Octavian, who claimed to succeed to Julius Caesar. Caesar himself had seized total power in Rome by a mix of military might and conquest-funded demagoguery — before being stabbed to death by partisans of the old republic. His only legitimacy was the might of his armies — and popular support among voters bought with wealth stolen by said armies or produced by their enslaved victims. To add insult to injury, Octavian, Tiberius and their successors claimed to be Gods, which the monotheistic Jews refused to recognize, which led the Jews repeatedly to rebel and the Romans to mercilessly crush them. There was no pretense whatsoever from Roman conquerors to be serving the interests of the Jews, only to subjugate them. There was no claim to superior Justice, only to Force. Those who claim today that Jesus's saying supports the State as being your friend and its taxes as being anything but theft are the worst enemies and corruptors of the faith, violating the first two Commandments: adoring a false idol (the State) above the True God, and claiming to speak in the name of God while distorting His word.
What Jesus also clearly doesn't possibly mean is that you should literally take all the coins you have with Caesar's face on them (i.e. every single one of them) and give them all (i.e. everything you earn) to the Roman tax collectors. Even tax collectors don't want that: indeed State officials are slavers and not mere brigands, and they want you to keep enough to survive and produce and prosper somewhat so they may tax you again the next year, and every year thereafter. Jesus does not advocate suicide by relinquishing all your life's earnings to Caesar, just like he doesn't advocate suicide by rebelling against Caesar. He's advocating the opposite of suicide, he's advocating doing what you need to do to survive, and brilliantly demonstrating what he means to boot!
By giving an answer that won't get him killed one way or the other, Jesus leads by example: the right way to live is to reject false dichotomies, that lead to death, and instead choose life. The question was a false question. Like Zen masters, he says neither "Yes" nor "No", but "Mu" — he's un-asking the false question. And instead he's asking the real question: you must think for yourself and determine what you need to give to Caesar, according to what belongs to him that you personally owe him — i.e. according to the criterion of Justice. At the same time, he demonstrates by his example that you must be wary that Caesar's power is real indeed, and must not ignore his superior Force.
Jesus wants you to think in terms of Justice. Clearly, what the tyrant justly deserves is violent death — like the 23 deadly stab wounds inflicted on the original Caesar. That's what belongs to Caesar. But it's not yours to give it to him. That's not what you personally owe him, for you do not have that power, and you do not have this responsibility (unless you personally do, and then what the hell are you waiting for?). You don't possess the means of overthrowing Caesar. Jesus himself didn't. And if you did, you'd be the next Caesar itself! Just killing the evil tyrant isn't enough to restore Justice: killing the original Caesar only led to more civil wars, hundreds of thousands of untimely deaths, and the crowning of Octavian as an even worse devious ruler. To restore Justice, instead you need... well, I'll get to the only possible way to it, that Jesus not only tells but demonstrates.
And so, inasmuch as we all hate Caesar who indeed deserved brutal death, stabbing him is (generally) not the right thing for you to do. Jesus implicitly but clearly leads by example, demonstrating that you should not betray yourself in either mind or body when dealing with the State and its evil followers. Caesar deserves what's right for him, but first you owe to yourself what's right for you to do: you must render to God what belongs to God. Thus, the right thing for you personally to do is often (but not always) to acknowledge the superior force that Caesar possesses and pay the taxes he demands — so you may importantly go on with the rest of your life. For your first responsibility is not to Caesar but to yourself, and that's what will allow you to survive, live, and pursue your superior goals. You do possess superior, positive goals — "worshipping god" in first century Jewish parlance. Caesar is an obstacle to positive goals (something or someone who stands on the way to your goals and make them harder to reach), but not a negative goal (i.e. someone you have a positive duty to defeat rather than merely to avoid); of course he is even less a friend (someone or something that helps you reach your goals and makes them easier to reach) or worst of all a positive goal (i.e. someone you have a positive duty to help and glorify — those who worship the State are indeed devil-worshippers astray from all decent religion). Don't let that obstacle keep you from your positive goals, from that which belongs to God that you owe to render Him: fructifying the talents that He entrusted to you (which is the topic of another parable).
Therefore, to quote that latter-day christian prophet G. K. Chesterton, be wary that "to have a right to do a thing is not at all the same as to be right in doing it." Yes, Caesar deserves violent death, and it would only be justice towards him if you delivered it; but unless you are going to actually seize power and be a better Caesar than Caesar, then it would be counter-productive to indulge in such terrorist violence and the wrong thing to do for you and for all the victims of the increased violence that your action will undoubtedly unleash. Additional violence as such doesn't breed more justice, it only breeds more violence. Additional understanding of Justice on the other hand breeds more justice, and if it eventually leads to many Caesars meeting their well-deserved brutal fate, it also and importantly leads to less violence overall — for Justice is the minimization of violence indeed.
And a better understanding of Justice is exactly what Jesus explicitly invites you to pursue, when he tells you to think in terms of what you owe to Caesar — who is a placeholder for everyone in general, even the very worst person on Earth. What he wants is to foster Justice, which begins in people's minds. Your religious duty according to Jesus is to study and understand Justice, thus furthering it. This way, and this way only, can Force be eventually tamed, and Justice eventually restored — and established in the first place.
Jesus wants you to think in terms of Justice, but also to understand and respect Force — and most of all, he wants you to understand the glaring difference between the two.