Few words are surrounded by as much confusion and misunderstanding as legalism. Many modern-day believers carelessly use it to dismiss any strong call to holiness or high standards of conduct that reflect the righteousness of God. However, though the term is never used in the New Testament, we may biblically define legalism as any attempt to earn God’s acceptance and favor by means of human exertion or outward conformity to the Law; i.e. to earn salvation by works of the law.
This was the cause of the first major theological debate in the early church. Acts 15:1 announces, “some men came down from Judea and began teaching the brethren, ‘Unless you are circumcised according to the custom of Moses, you cannot be saved.’” Thankfully, the gospel of grace was rescued from some converted Pharisees’ attempt to return others to the bondage of the Law by requiring Gentiles to become Jews physically before they could experience spiritual salvation. Years later, similar Judaizers promoted the same doctrine throughout the region of Galatia to the degree that Paul was compelled to write a whole letter correcting their errors. His argument is summed up in this one statement: “I do not nullify the grace of God; for if righteousness comes through the Law, then Christ died needlessly” (Gal 2:21). Certainly legalism—biblically defined—is something to oppose.
However, it must be noted that many believers wrongly use the term legalism to refer to what is better called Pharisaism, that is, a preoccupation with externals while ignoring the internal—the issues of the heart. Those who promote and practice Pharisaism believe holiness is measured merely by outward conformity to rules and regulations, rather than the transformation of desires and motives of the heart. However, Jesus shattered this misguided measurement of spirituality by reminding His disciples that unless the heart-causes of outward behavior are addressed sanctification has been hindered, not helped (Matt 15:17-20). Certainly it is possible for a person to appear to be godly, due to outward conformity, and yet have a heart that is very far from God.
Therefore, let us pursue holiness without which no one will see the Lord (Heb 12:14). But let us beware of Pharisaism, which deceives self (more deadly than deceiving others) and results in eternal condemnation.