Summary: In many modern churches, legalism is no more than acknowledging that the Lord has given to His Church a body of legislation that He expects to be taught and obeyed.
During my decades of Christian ministry, the terms “legalism” and “legalist” have progressively been bandied-about within modern churches and their preachers/pastors. These terms have, primarily, been used to describe and condemn those Christians and churches that believe that there is more to being a follower of Christ than simple belief in Jesus and having an emotional attachment toward the Savior. The modern churches assert that God's grace negates the necessity of observing all of the commands and statutes delivered by Christ Jesus and His Apostles. For such churches, legalism is acknowledging that the Lord has given to His Church a body of legislation that He expects to be taught and obeyed.
From my study of the Scriptures, such a definition of legalism is without Biblical support. Biblical legalism is when a person or church places demands and restrictions on a Christian that are not found in the Scriptures. Also, Biblical legalism is when a person or church emphasizes the minutiae of the New Testament's law above the foundational virtues such as faith, hope, and love.
Jesus condemned the legalism that was promoted by the Pharisees, Saducees, scribes and lawyers of His day. He told His disciples not to follow in their foot-steps, saying, “Watch out and beware of the leaven of the Pharisees and Sadducees (Matthew 16:6).”
The Jews' spiritual leaders were guilty of both facets of genuine legalism. First, they added numerous rules and regulations to the already oppressive 613 commandments and statutes of the Mosaic Law. Jesus said to His followers that, by their adding rules and regulations, the Jewish religious authorities “tie up heavy burdens and lay them on mens' shoulders (Matthew 23:4).” These “heavy burdens” were man-made rather than being Divinely inspired; which lead Jesus to say, in Mark 7:7, “But in vain do they worship Me, teaching as doctrines the precepts of men.” Secondly, in their obsession to teach and enforce both the minutiae of the Mosaic Law and their precepts and traditions of men, Jesus said that the Pharisees, Sadducees, scribes and lawyers neglected “the weightier provisions of the Law: justice and mercy and faithfulness (Matthew 23:23).”
Today's Christians – individually and collectively- must stay on the alert and examine their religion and be diligent in avoiding the legalism that Christ condemned :
Christian churches must not add rules and restrictions not taught by Christ and His Apostles. The words of the Apostle Paul are relevant as he wrote: “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 yourself to decrees, such as, 'Do not handle, do not taste, do not touch!'... in accordance with the commandments and teachings of men? These are matters which have, to be sure, the appearance of wisdom in self-made religion and self-abasement and severe treatment of the body, but are of no value against fleshly indulgence.” Christian preachers and teachers are authorized to explain the ways we can apply moral and spiritual principles to our daily lives; but, they must be careful not to make their specific applications as authoratative as Scripture. Each Christian must be careful to not push upon others rules and regulations that they have adopted for their own spiritual walk but are not enjoined in the Scriptures. Where the Bible is silent, we must be silent.