Strange indeed is the complacency with which modern men can say that the Golden Rule and the high ethical principles of Jesus are all that they need. In reality, if the requirements for entrance into the Kingdom of God are what Jesus declares them to be, we are all undone; we have not even attained to the external righteousness of the scribes and Pharisees, and how shall we attain to that righteousness of the heart which Jesus demands? The Sermon on the Mount, rightly interpreted, then, makes man a seeker after some divine means of salvation by which entrance into the Kingdom can be obtained. Even Moses was too high for us; but before this higher law of Jesus who shall stand without being condemned? The Sermon on the Mount, like all the rest of the New Testament, really leads a man straight to the foot of the Cross.
J.Gresham Machen, Christianity and Liberalism | Image source: Lightstock