Consider this a preface to, and effective summary of, what I hope to offer in a long-promised post on legalism tomorrow.
Quoting Tim Keller:
Quoting Tim Keller:
Tertullian said, "Just as Christ was crucified between two thieves, so this doctrine of justification [by faith alone] is ever crucified between two opposite errors." These errors continue to "steal" the gospel from us. They are "legalism" and "liberalism". On the one hand, "legalists" have a truth without grace, for they say or imply that we must obey the truth in order to be saved. On the other hand, "liberals" have a grace without truth, for they say or imply that we are all accepted by God regardless of what we decide is true for us. But those with truth without grace, do not really have the truth, and those with grace without truth, do not really have grace. In Jesus we behold the glory of the one "full of grace and truth".
De-emphasize or lose one or the other of these truths, you fall somewhat into legalism or somewhat into license and you eliminate the joy and the "release" of the gospel. Without a knowledge of our extreme sin, the payment of the gospel seems trivial and does not electrify or transform. But without a knowledge of Christ's completely satisfying life and death, the knowledge of sin would crush us or move us to deny and repress it. Take away either the knowledge of sin or the knowledge of grace and people's lives not changed. They will be crushed by the moral law or run from it screaming and angry.
As Luther put it, the Christian is simul justus et peccator (simultaneously accepted, yet a sinner). We are more sinful than we ever dared believe, but through Christ we are more accepted than we ever dared hope. When the gospel dawns on the soul, it becomes a transforming power (Romans 1:17). Instead of seeing the law of God as an abstract moral code, Christians see it as a way to know, serve, and resemble their Master. Instead of obeying to make God indebted to them, they obey because they are indebted to him. Instead of being driven by an anxious sense of being unacceptable, they are empowered by grateful joy. The difference between these two ways of morality could not be greater. Their spirits, goals, motivations, and results are entirely different.