The Golden Rule is the concluding verse of the major part of the Sermon on the Mount, for all the verses that follow it are but a long, although significant, postscript. Like Matthew 5:48, the verse that concludes the first chapter of the sermon, the Golden Rule aptly summarizes all that has gone before it and then lifts the eyes of the reader to Jesus Christ, who is the only possible source of such goodness. From this point on, Jesus turns to a series of warnings designed to keep His listeners from falling by the wayside through unbelief, apathy, deceit, hypocrisy, or discouragement.
This does not mean, of course, that the verses that follow are unimportant. For although they are largely in the nature of a postscript, for some persons, perhaps yourself, they could be the most important verses of all. For instance, we may imagine a man who has agreed with the bulk of this teaching but who thinks he can put it into practice merely by exerting a little more effort while continuing in the same general direction he is going. To such a man these verses are a reminder that the Christian life must begin with an about-face and that it cannot be carried on without a personal commitment to the Lord Jesus. Another man finds himself thinking that religion is a good thing, and he determines to go on listening to other rabbis and teachers. Jesus warns him that there are many false prophets who have gone out into the world and that the religion caught from these sources will not save him. In the same way, He warns the man who would settle for an outward profession of Christianity without experiencing a change in his heart, and He cautions that the only valid religious life must be built upon Himself as the only firm and therefore adequate foundation. Quite obviously, these warnings apply to many who are grappling with the claims of the Gospel in the twentieth century.
I want you to see, however, that these concluding thoughts also had a particular poignancy for those who were listening to this Sermon for the first time, those who were hearing the Sermon in Galilee presumably during the earliest months of Jesus’ ministry.
We must remember here that Jesus was speaking of ultimate things to those who as yet had no knowledge of His coming death and resurrection. Those events, on which salvation through faith depended, were yet years away, while in between there would be days in which the charm and popularity of the Galilean ministry would give way to insults, trials, scorn, and great danger. What was to happen to His hearers during the intervening years? Was the teaching of the Sermon on the Mount to become for them only a beautiful dream buried somewhere in their memories of the past? Was it to be enshrined as something very lovely but known to them to be totally impractical? Or, on the contrary, was it to challenge them to keep on in the Christian life, and to enter into the joyful and abounding life that the Lord Jesus Christ had promised through the power of the indwelling Holy Spirit? Certainly, Jesus was calling for the last of these possibilities, and He was telling his hearers, “Keep on. Do not fall by the wayside. For if you do keep on, one day you will see the gate clearly and you will pass through to life everlasting.”