Legalism and antinomianism are both enemies of the gospel. They are polar opposites, attacking the gospel from different sides. Antinomianism makes an indirect attack on the gospel by aiming its primary assault against the law. Legalism aims directly at the gospel. Antinomianism attacks the believer’s sanctification. Legalism attacks the believer’s justification. Antinomianism denies the authority of the law over a believer. Legalism denies the free grace of the gospel. There is no question that Scripture addresses both problems in several places. Romans 6, 1 Corinthians 6:9–11, Hebrews 12:14–17, and 1 John 5:1–5 are just a few of the passages that emphasize the necessity of the believer’s sanctification for salvation. Likewise, Romans 3:21–5:21, Galatians 3–4, Ephesians 2:8–9, as well as many others, teach that justification is by grace through faith in Christ alone, apart from the works of the law.
Justification by faith alone is the cornerstone of scriptural truth. In the seventeenth century, Johann Heinrich Alsted wrote: “The article of justification is said to be the article of the standing or falling church.” Those words are often attributed to Martin Luther, and though the exact quote may not have originated in Luther’s writings, there is no question that Luther and all the other Reformers agreed with that statement. Protestantism, and indeed all of Christianity, stands on the truth of justification by faith alone. Christianity falls whenever that truth is denied. It is for this reason that legalism, which directly attacks the gospel and justification by faith alone, is the greatest enemy of the gospel. Antinomianism is a terrible enemy, but legalism is more virulent still.
Legalism is hard to combat for most Christians because they do not have a clear definition of what it is. Most Christians think of legalism simply as man-made rules—for example, “Do not smoke, do not drink, do not dance.” Colossians 2:20–22 certainly condemns such man-made religion:
If with Christ you died to the elemental spirits of the world, why, as if you were still alive in the world, do you submit to regulations—“Do not handle, Do not taste, Do not touch” (referring to things that all perish as they are used)—according to human precepts and teachings?
In Scripture, though, legalism refers to two things: Trusting in ceremonial works of righteousness for salvation and/or trusting in moral works of righteousness for salvation.
The ancient Jews thought that they could find acceptance with Yahweh if they were circumcised, performed the required sacrifices, kept the Passover, and lived in faithful obedience to the Torah. Christians can be guilty of the same error with respect to baptism, the Lord’s Supper, and the Ten Commandments when they trust in any of them for their salvation. Thus, Paul wrote in Romans 2:28–29:
For no one is a Jew who is merely one outwardly, nor is circumcision outward and physical. But a Jew is one inwardly, and circumcision is a matter of the heart, by the Spirit, not by the letter. His praise is not from man but from God.
If you substitute “Christian” for “Jew” and “baptism” for “circumcision” in those verses, you see how Paul’s words relate to Christians.
The great problem with legalism is that it undermines the whole doctrine of salvation. The first way it does that is by emphasizing the outward or external to the neglect of the inward or internal. It emphasizes man’s outward performance of ceremonies and outward good works to the exclusion of those good works being produced by a new heart. The great spiritual change from darkness to light, from slavery to freedom, is described by Paul in Romans 6:17: “But thanks be to God, that you who were once slaves of sin have become obedient from the heart to the standard of teaching to which you were committed.” True obedience is not just outward conformity but flows from a changed heart. That changed heart is what God promised in Ezekiel 36:26: “And I will give you a new heart, and a new spirit I will put within you. And I will remove the heart of stone from your flesh and give you a heart of flesh.” The effectual calling of God begins with the new birth. Until the tree is made good, the fruit cannot be good.
The second problem with legalism is that it substitutes a person’s faithfulness for saving faith. Faith and faithfulness are not the same thing. Faith looks away from self to Christ. Faithfulness depends on self to fulfill the requirements of the law. Faith is an empty hand stretched out to God. Faithfulness is a hand filled with supposed good works that are really filthy rags apart from faith in Christ. In salvation, saving faith always takes the lead and good works follow or flow from such faith. Reversing the order is deadly.
The third problem with legalism is that it replaces justification by faith alone, which is once for all, with a doctrine of final justification that is not realized until the last judgment. Legalists are often very subtle at that point. They will define justification as through faithfulness alone (not faith alone) and will wrongly describe the last judgment as a “final justification.” Thus, they confuse judgment and justification. The justification taught in the Scripture is once for all and happens in time and space before the day of judgment.
The fourth problem with legalism is that it confuses justification and sanctification. It either blends them together (faith plus works) or it places sanctification first and suspends justification until the end of life. The gospel scheme of salvation always places justification first with sanctification flowing from the new heart of a believer. While James 2 is often pitted against the teaching of Paul, both authors of Scripture teach the same truth. James 2:18 says, “Show me your faith apart from your works, and I will show you my faith by my works.” Galatians 5:6 says, “For in Christ Jesus neither circumcision nor uncircumcision counts for anything, but only faith working through love.” True faith is evidenced by good works, and justification is by faith alone, but justifying faith is never alone or apart from good works.
Finally, legalism negates true assurance of faith. Cardinal Bellarmine once said, “The greatest of all Protestant heresies is assurance.” No one can have assurance of salvation if, as legalists assert, justification is not finalized until the last judgment. Yet Scripture is clear that Christians can have assurance of their salvation (see Col. 2:2; Heb. 6:11; 10:22; 11:1; 1 John 5:13). The assurance of salvation flows from the new birth, justification by faith, adoption into the family of God, and sanctification. What a wonderful God of grace and what a wonderful salvation.