The Law of Christ and the Powers That Be

Though you'd never know if from reading what much of the evangelical and neo-Calvinistic world has to say about "the kingdom," the Reformed view states that "the church is the kingdom of our Lord Jesus Christ" (WCF XXV.2). Still, the distinction between the civil and spiritual kingdoms, sharp though it may be, is often blurred at the very point where those two lines intersect:

The individual believer.

Because we hold dual-citizenship in the kingdoms of Christ and culture, our allegiances can be difficult to determine, and sometimes even conflicting. For this reason the Bible has much to say about keeping our devotion straight.

We are forbidden by Scripture, for example, from waging a spiritual battle with carnal weapons (II Cor. 10:3-5), and yet we are permitted to disobey the civil magistrate when its laws are in conflict with Christ's (Acts 5:29).

But those are easy. What about more difficult dilemmas like, for example, fighting civil battles with spiritual weapons? Ought we to bother ourselves with civil concerns at all? And if so, at what point, if any, may we legitimately disobey those "who wield not the sword in vain"?

And should we quote Scripture when we do it?