The first kind of legalism is where the law of God is kept in order to attain salvation. This is a heresy, a completely false doctrine. According to the following Scriptures: Romans 3:28, 4:5, and Galatians 2:21, we are not able to attain salvation by our keeping the law. Therefore, to try to gain salvation through one’s efforts is a false teaching. It is so bad that those who hold to it cannot be Christians since it would deny salvation by grace through faith.
The second form of legalism is where a person tries to keep or maintain his salvation by keeping the law. This is also a false doctrine. We receive our salvation by faith (Eph. 2:8-9), not by our ability to be good because no one does good (Rom. 3:10-12). As Rom. 3:28, 4:5, and Gal. 2:21 clearly show, we are justified by faith, not by faith and works. Furthermore, there are strict warnings about attempting to keep the law in order to maintain salvation: Gal. 3:10, “For as many as are of the works of the Law are under a curse; for it is written, ‘Cursed is everyone who does not abide by all things written in the book of the law, to perform them.’” And James 2:10, “For whoever keeps the whole law and yet stumbles in one point, he has become guilty of all.” So, if a person is seeking to be either saved by his works (Law) or maintain his salvation by his works (Law), then he is under obligation to keep all of it, and if he does not then he is guilty before God. Furthermore, consider Jesus’ words in Matt. 7:22-23, “Many will say to me in that day, ‘Lord, Lord, did we not prophesy in thy name? and in thy name cast out devils? and in thy name perform many wonderful works?’ 23 “And then I will profess to them, ‘I never knew you: depart from me, ye that work iniquity.’” Christ condemned those that appealed to their actions for their salvation. So it should be obvious that we do not keep our salvation by our efforts.
The last kind of legalism, where a Christian keeps certain laws and regards other Christians who do not keep his level of holiness with contempt, is a frequent problem in the church. Now, it is important to understand that all Christians are to abstain from fornication, pornography, adultery, stealing, lying, etc. Christians do have a right to judge the spirituality of other Christians in the areas where the Bible clearly speaks. However, in the debatable areas we need to tread carefully, and this is where legalism is more difficult to define. Rom. 14:1-12 says that we are not to judge our brothers on debatable issues. One person may eat certain kinds of foods where another would not. One person might worship on a particular day where another might not. We are told to let “every man be fully persuaded in his own mind” (Rom. 14:5). As long as our freedom does not violate the Scriptures, then everything should be all right.