Legalism in Christian living may appear in two different forms, though often legalistic Christians practice both forms together.
In the first form of legalism Christians pursue sanctification by trying to keep the Law through self-effort. This legalistic approach to sanctification opposes the principle of grace, neglects the power of the Spirit, and leads to spiritual frustration and failure in attempting to conquer the sinful flash.
Christians experience freedom from bondage to legalism and victory over sin when they live by grace, rely on the Spirit, and obey Scripture through the power Spirit-produced love.
A second form of legalism imposes on Christians a code of conduct of human regulations about external observances and deeds. This form of legalism requires outward conformity to certain human regulations as a measure of religious achievement; does not properly consider one's inner character, motivation, power, and goals as essential factors in biblical spirituality; and appeals to fleshy performance and human pride. Paul evidently had this form of legalism in mind when he referred to Christians who submit to regulations "in accordance with the commandments and teachings of men" (Col. 2:22). Paul warned the Colossian Christians that their legalistic regulations were contrary to their identity with Christ. "If you have died with Christ to the elementary principles of the world why, as if you were living in the world, do you submit yourselves to decrees, such as, "Do not handle, do not taste, do not touch!" (2:20-21). Submission to these ascetic prohibitions is supposed to produce spiritual victory over the flesh. Instead, legalistic asceticism has two serious problems: It is the practice of "self-made religion" (2:23), and it does not sanctify (2:16-23), for it is of "no value against fleshy indulgence" (2:23)
Both forms of legalism involve a fleshy self-effort to conform to an outward code instead of an inward willingness to obey God from a Spirit-filled heart.
- From 'Understanding Christian Theology"
