The New Testament views Christian obedience as the practice of “good deeds” (works). Christians are to be “rich in good deeds” (1 Tim. 6:18; cf. Matt. 5:16; Eph. 2:10; 2 Tim. 3:17; Titus 2:7, 14; 3:8, 14). A good deed is one done (a) according to the right standard (God’s revealed will, i.e., his moral law); (b) from a right motive (the love to God and others that marks the regenerate heart); (c) with a right purpose (pleasing and glorifying God, honoring Christ, advancing his kingdom, and benefiting one’s neighbor).

Legalism is a distortion of obedience that can never produce truly good works. Its first fault is that it skews motive and purpose, seeing good deeds as essentially ways to earn more of God’s favor than one has at the moment. Its second fault is arrogance. Belief that one’s labor earns God’s favor begets contempt for those who do not labor in the same way. Its third fault is lovelessness in that its self-advancing purpose squeezes humble kindness and creative compassion out of the heart.

In the New Testament we meet both Pharisaic and Judaizing legalism. The Pharisees thought that their status as children of Abraham made God’s pleasure in them possible, and that their formalized daily law-keeping, down to minutest details, would make it actual. The Judaizers viewed Gentile evangelism as a form of proselytizing for Judaism; they believed that the Gentile believer in Christ must go on to become a Jew by circumcision and observance of the festal calendar and ritual law, and that thus he would gain increased favor with God. Jesus attacked the Pharisees; Paul, the Judaizers.

The Pharisees were formalists, focusing entirely on the externals of action, disregarding motives and purposes, and reducing life to mechanical rule-keeping. They thought themselves faithful law-keepers although (a) they majored in minors, neglecting what matters most (Matt. 23:23-24); (b) their casuistry negated the law’s spirit and aim (Matt. 15:3-9; 23:16-24); (c) they treated traditions of practice as part of God’s authoritative law, thus binding consciences where God had left them free (Mark 2:16-3:6; 7:1-8); (d) they were hypocrites at heart, angling for man’s approval all the time (Luke 20:45-47; Matt. 6:1-8; 23:2-7). Jesus was very sharp with them on these points.

In Galatians, Paul condemns the Judaizers’ “Christ-plus” message as obscuring and indeed denying the all-sufficiency of the grace revealed in Jesus (Gal. 3:1-3; 4:21; 5:2-6). In Colossians, he conducts a similar polemic against a similar “Christ-plus” formula for “fullness” (i.e., spiritual completion: Col. 2:8-23). Any “plus” hat requires us to take action in order to add to what Christ has given us is a reversion to legalism and, in truth, an insult to Christ.

So far, then, from enriching our relationship with God, as it seeks to do, legalism in all its forms does the opposite. It puts that relationship in jeopardy and, by stopping us focusing on Christ, it starves our souls while feeding our pride. Legalistic religion in all its forms should be avoided like the plague.