"But woe to you, scribes and Pharisees, hypocrites! For you shut the kingdom of heaven in people's faces. For you neither enter yourselves nor allow those who would enter to go in." (Matthew 23:13-14)
Jesus starts by warning the crowd and his disciples that the scribes and Pharisees "shut the kingdom of heaven in people's faces." By teaching a gospel contrary to grace alone through faith alone in Christ alone they are shutting the kingdom of heaven up for people. The ESV Study Bible says, "The teachers of the law and the Pharisees are false leaders who have drawn the people away from the kingdom of heaven instead of toward it." Remember Paul's warning to the churches of Galatia about false teachers? "If anyone is preaching to you a gospel contrary to the one you received, let him be accursed" (Gal. 1:9).
The gospel is the most essential thing in all of life. The true gospel promotes Christ and him crucified as the only source of eternal life. When teachers come teaching some other gospel Paul says to let them be damned. This is serious! We must not add to Christ's finished work on the cross. Anything we add to the true gospel makes us false teachers. When we add to the gospel we are being like the Pharisees and shutting the door of the kingdom in people's faces. But we must also examine our own hearts. We must dig deep into God's Word to see whether or not we are adding to the gospel in our own lives. Legalism is nothing more than finding your justification in works rather than Christ. May we be very careful and heed the warning of Jesus. May we not be hypocrites in practice like the Pharisees but rather rest in Christ's finished work on the cross.
Grace upon grace,