Avoiding legalism is firstly a matter of rightly understanding what it is. To begin with, we must reject incorrect definitions of legalism. One such error is the belief that interpreting Scripture literally and applying it to modern living is a form of legalism.
For some people, legalism is another word for taking Scripture literally, and making claims that God actually commands or forbids certain actions in the 21st-century. Apparently, to remain a minister of grace in the eyes of these folks, you need to keep all teaching broadly generic, and keep Scripture wrapped in its historical cocoon. If you attempt to draw a line from text to Tuesday morning, you’re a wooden literalist, and a legalist. (On the other hand, if you take their advice, you’ll be told by others that what people really want is “practical sermons” that “deal with the real world”.)
Now where there’s smoke, there’s sometimes fire. And a jitteriness about sermons making modern applications from ancient texts isn’t to be solely attributed to disingenuous hearts. Some of it comes from having heard one too many preacher produce applications from thin air. Perhaps you’ve sat listening to a sermon and been jolted by applications that seemed to burst in the door unexpectedly (for nothing in the text warned us they were coming). That’s not to say such applications are Scripturally indefensible or, for that matter, equally destructive. The problem is, often enough, good pastors and parents have correctly instructed their charges regarding Christian living, but have done so with little warrant from Scripture. The warrant may or many not have been there in Scripture; too often it was not made clear.
A generation of people were simultaneously told that everything must be “Bible-based” and that such-and-such an application was “obviously what godly people have always done”. The dissonance between the two has produced some scepticism. It’s also produced a pendulum swing in the other direction, where people supposedly devoted to the authority of Scripture will not let it speak outside its own covers. If Scripture does not supply the application in the text, they regard it as legalism to supply one. And such neo-legalists are in danger of becoming libertarians at the same time, for in their minds, Scripture forbids little of what they do.
Once a pastor gives an apparent application of Scripture from the pulpit, he is, in essence, bringing such a matter to the consciences of his people as a matter of obedience or disobedience. This task he must not shirk, but this task he must do very skilfully. For if he insists people do what God has not called for, God may one day say to him, “This I commanded not, neither came it into My mind.” On the other hand, should the preacher decide that certain applications would be upsetting and unpopular and therefore skirts them, he will be guilty of having failed to unleash the power of Scripture to speak to all of life.
Warrant is the issue here. If there is warrant to connect a Scripture to contemporary life, then a reasonable application can, and in fact, has to be made. The right approach is neither to retreat to applications made purely on the assertive confidence of the preacher, nor to move out to the irony of legalistic antinomianism. What is needed is for teachers of Scripture to think clearly about the warrant for applying Scriptural principles to contemporary life.
The three sources of knowledge are authority, reason and experience. Authority is Scripture. Reason is the God-given ability to inductively or deductively reach the truth through logic. Experience is observation and analysis of observable experience in the universe. If reason and experience provide us truth about matters like music, aesthetics and culture (and they do), and Scripture expects us to worship with music, approve what is excellent and obey God in the world (and it does), then there is sufficient warrant to make applications about such things. That isn’t legalism; that’s furnishing a believer for every good work (2 Tim 3:17).
If a warrant is tenuous, we ought to say so. On the other hand, if the warrant is established through sound reason, and the good judgement of experts, critics, professionals, or other authorities in that field of knowledge, it is not legalism to make the application. In fact, it’s the opposite. It is being responsible enough to apply truth from Scripture to the lives people lead.