Legalism is not only possible for Christians, it is likely. The default leaning of our flesh is toward autonomy. That autonomy can manifest in overt rebellion (antinomianism) or in self-righteous religiosity (legalism), but both are manifestations of a separation of God’s Law from God Himself.
You probably see the label “antinomian” being used. It is a serious charge. It suggests that someone is anti-law and therefore, by implication, pro-sin. It tends to be used of those who don’t elevate the Law as much as they apparently should. Undoubtedly there are some antinomians who are genuinely pro-sin, but I haven’t met many. I have met a lot who might be labeled “antinomians” who do not see the Law as the solution to the profound reality of sin, and who, incidentally, live lives characterized by greater integrity and with more fruit of the Spirit evident than some who like to criticize them.
As preachers we need to wrestle with these issues. We stand and speak not only of how to be saved, but also about living the Christian life. For many those are two separate messages. We are saved by grace, they say, but we live the Christian life by determined obedience to the Law. Somehow this two-part message should feel very awkward for us.
We need to devour our Bibles and get a sense not only of the instructions in there, but also the source of those instructions. Jesus seemed to suggest that His way would mean a greater and a deeper holiness, one that would surpass that of the fastidious Pharisees. Yet we tend to think of the Old Testament folks as having a far more demanding legal code than we could cope with. Are we missing something? Should we demand more strongly that our listeners keep more laws? Or is there something implicit in the New Covenant that Jesus instituted that leads to a greater awareness of sin, and a greater victory over it?
The New Testament is clear that this life will be a struggle between the flesh and the Spirit, so perfection is unrealistic. But is there something in the New Covenant that means we can keep in step with the Spirit, that we can delight to please our God, that we can live lives of greater moral integrity out of a heart-stirred delight rather than through external pressure?
Let’s beware of an inadequate understanding of sin and a wholly inadequate approach to living lives that please God – for that is what legalism is: weak on the problem and a flimsy solution to it.
Perhaps it would do us preachers good to take a book like Galatians and read it through again and again. If we bring with us the question of what does it look like to live the Christian life, what is sin and what is the solution for the believer?, then these questions might gradually open up Paul’s teaching there and bring new life to our ministry. It cannot hurt. Twenty, thirty, fifty times through Galatians would help us all. Shall we?