Paul’s epistle to the Romans “is purest gospel,” Martin Luther wrote in his preface to Romans in his translation of the New Testament. It is not hard to understand why Luther said that. Within the first few verses of Romans, Paul refers to himself as set apart to proclaim “the gospel of God” and then focuses on the gospel as the source of the righteousness of God for believers in Christ (1:1, 16–17).
But as we have seen, Paul does not begin his exposition of the gospel with a definition of the gospel; rather, he spends several chapters setting the stage for that explanation by explaining why human beings need the gospel. Sin and the estrangement it creates between people and their Creator mean that sinners need reconciliation with God. And sin is a universal condition, afflicting Jew and Gentile alike. Every man, woman, and child—except Jesus—has broken the law of God (Rom. 1:18–3:18). “All have sinned and fall short of the glory of God” (3:23).
Facing this predicament, fallen people have the natural propensity to try to do better, to endeavor to build up a record of goodness and righteous works that will outweigh their transgressions. This is a futile endeavor. We know what is good from the law of God, but sinners who are under the law—sinners who try to obtain their righteousness before God by keeping the law—have their mouths stopped when they try to plead their own righteousness before God. If we seek to keep the law in order to be justified—in order to be declared righteous by God and no longer under His wrath—we will fail, for the law of God does not give us what we need to be reckoned as righteous. Instead, it gives us the knowledge of sin, telling us that we are sinners (vv. 19–20).
Note that in today’s passage, Paul is not giving the full doctrine of the law of God. The law does more than give us knowledge of sin and convict us of our sin. It also tells us what pleases God, and it restrains sin, keeping people from being as bad as they possibly could be (Rom. 7:12; 1 Tim. 1:8–11). But with respect to the justification of sinners, Luther says, “The law was given only that sin might be known.”
Today’s passage has the Mosaic law primarily in view but not to the exclusion of the law on the conscience. God’s eternal moral law is contained within the Mosaic law (alongside the ceremonial and civil law), but not everyone has access to Scripture. However, the moral law is found also on our consciences, where it testifies that we have broken it (Rom. 2:14–16). Thus, God’s moral law, however we possess it, only condemns us with respect to justification.