At the very end of the Sermon on the Mount we read that the people who heard Jesus "were astonished at his doctrine; for he taught them as one having authority, and not as the scribes" (Matt. 7:28-29). The statement indicates that the unprecedented authority of the Lord Jesus Christ was startling to his contemporaries. But surprising as this note of authority was, the standard that Jesus set before men was more startling still.

There is a fourth reason why human righteousness is unacceptable to God, and it is most important. Human righteousness is actually a different kind of righteousness from that which God requires. God asks for divine righteousness, and human righteousness is not divine righteousness at all. 

Jesus' words were also difficult, however, because he was not saying that in order for a man to get to heaven he must have a slightly higher degree of the same kind of righteousness that the scribes and Pharisees had been accumulating. The first part of the Sermon should have dispelled any thought of that. He was saying that if a man was to get to heaven he must somehow have a different and better righteousness than these men were showing. 

Have you ever asked yourself in the course of your own study of the Word of God if there is a theme to the Old Testament, and if so what it is? It is a question with which every Old Testament theologian must grapple and for which a variety of answers have been given. 

It is not only true that the Lord Jesus Christ fulfilled the law, however; he also fulfilled the prophets as the verse implies, only he did this in an entirely different way. When we speak of prophecy we are speaking of direct statements in the Old Testament about the one who was to come to deliver Israel and redeem mankind, statements that told who he would be, where he would be born, what he would do, how he would suffer, and what would be the ultimate outcome of his suffering. Thus, when Jesus said that he had come to fulfill the prophets, he meant that he had come to fulfill the great statements that had been made about him in the Old Testament.