There's a certain situation that always brings to mind the verse, "Be wise as serpents, harmless as doves" (Matt. 10:16). It's usually a situation where a person who is committed to be good is engaged with the powers of evil in the world. If I dare to quote a certain character from science fiction, "Spock, I've found that evil usually triumphs [over good] unless good is very, very careful."
I heard another proverb once from Keith Drury, "Don't wrestle with a pig. You both get dirty but the pig likes it." I think of the Parable of the Unjust Steward. A Christian in the halls of money and power is in a surreal world, an Alice in Wonderland.
The pacifists among us would say not to engage the worldly powers on their own terms. They would say that the person who dabbles in the world to try to do good inevitably infects themselves and cannot retreat. You start trying to bomb just the terrorists but you end up blowing away a whole country because they're all your enemy. Sinestro tries to harness the yellow energy of fear to fight evil but ends up evil instead.
I've never been able to go the whole way with pacifism or absolutism on these sorts of things. The Nazis are at your door looking for the Jews hiding in your attic and you lie even though you would rather not. So what of that rich and powerful member of the congregation to whom you have to give attention even though in God's eyes he or she is no more valuable than anyone else?
It's an age old story. Does Jimmy Stewart take the job at the bank or stick with the building and loan? In the movies, the most virtuous decision often prevails. In real life, it often doesn't. Is it "no compromise or die"? "Better dead than red"?
It's a quote about the circus of life--be wise as a serpent because the world is a surreal, strange place that will just as soon chew you up and spit you out. Be careful with power. Be constantly on your guard. Guard yourself when you get a little of it. Be harmless as doves. Constantly check your true motives. If you find yourself with venom in your hands, be careful who it gets on.