It is a deadly error of legalism which teaches that justification or salvation is by the works of the law. The legalists of Judaea said in their challenge of Paul's teaching, "Except ye be circumcised after the manner of Moses, ye cannot be saved" (Acts 15:1). But Paul's doctrine prevailed: "Knowing that a man is not justified by the works of the law, but by the faith of Jesus Christ, even we have believed in Jesus Christ, that we might be justified by the faith of Christ, and not by the works of the law: for by the works of the law shall no flesh be justified" (Acts 15:2-4; Gal. 2:16). The law can show us how unjust we are, and thus it can show us our need for justification, but the law can never justify: "Therefore by the deeds of the law there shall no flesh be justified in His sight" (Rom. 3:20). "If righteousness come by the law, then Christ is dead in vain" (Gal. 2:21).
The law cannot justify; neither can it sanctify. The law can show us that we are unholy, but it can never make us holy. The difference can be illustrated by two mountains: Mount Sinai and Mount Calvary. On Mount Sinai, God gave Moses His Law amid thunder and flame (Ex. 19-20). On Mount Calvary, amidst the horror of a great darkness, the Son of God paid the full penalty for our breaking of the Law (Matt. 27:32-50; 1 Cor. 15:3; 1 John 3:4). Mount Sinai shows us our dire condition as lawbreakers (Rom. 3:20). Mount Calvary reveals our Savior. Without the cross, the Law brings hopelessness. Without the law, the Gospel is meaningless. Thus both are essential, and inseparable. The key to living the Christian life is not found at Mount Sinai, but it is found at Mount Calvary.
Paul argued strongly that the Christian life is to be continued based upon faith, not on the Law: "This only would I learn of you, Received ye the Spirit by the works of the law, or by the hearing of faith? Are ye so foolish? having begun in the Spirit, are ye now made perfect by the flesh?" (Gal. 3:2-3). The Christian life is to continue just as it commenced! "As ye have therefore received Christ Jesus the Lord, so walk ye in Him" (Col. 2:6). Holiness does not come by seeking to keep the law in the energy of the flesh. Legality has been defined as "the flesh attempting to carry out the precepts of God." How successful is the flesh? Paul wrote, "For I know that in me, that is, in my flesh dwelleth no good thing: for to will is present with me; but how to perform that which is good I find not" (Rom. 7:18, 24).
However, the Believer does have a relationship with the Law. While the believer is not under the law (Rom. 6:14), the believer is not lawless (Rom. 6:1-2). We died to the law so that we might be married to Christ, and out of this relationship we bring forth fruit unto God (Rom. 7:4). The life of a true believer should manifest fruitfulness, not lawlessness. Legalists who try to put themselves under the law do not keep the law (Gal. 6:13; Acts 15:10), but those believers who walk in the Spirit do keep the law by way of the fruit of the Spirit: "That the righteousness of the law might be fulfilled in us, who walk not after the flesh, but after the Spirit" (Rom. 8:4; Gal. 5:22-23).