The Lord, after all, did say this as quoted above from the Sermon:

So, for many, that settles the issue.  Christians, calling Jesus "Lord," are to obey the Law as condensed to the Ten Commandments.  A look at the context and those who heard him deliver the Sermon (the crowd) shows otherwise.  Let's look!


The Crowd

The introduction to the Sermon speaks thus:


This speaks of two categories, the crowd and his disciples, and suggests that what follows, the Sermon on the Mount, was delivered only to his disciples.  The Beatitudes and his words that identify his hearers as the Light of the world and the salt of the earth (vs. 5:3-16) are surely directed to his disciples.  But when we come to the end of the Sermon and to the final comment of the evangelist, we read:

Though primarily addressing his disciples, "the crowd" also heard his words and its members were shocked.  This prompts the immediate question: if the Lord intended only to emphasize continuing obedience to the Law and the Prophets, why would they be shocked, to whom the Law and the Prophets, including the Ten Commandments, were the foundations of their nation and religion?  If they considered him a messianic candidate, his speaking with authority would not have shocked them.  Let us examine this "crowd."

Who comprised it? 

These were people of Israel who honored both the Law and the Prophets.  These scriptures constituted the fundamentals of their religion and the foundation of their nation, for which multitudes had given their lives to preserve and protect.  To them, many of whom were hearing him for the first time, Jesus was a new prophet whose intentions were yet unknown.  He came preaching the good news of the kingdom of God.  They were thinking that he might be their long promised messiah, the king of Israel, and it was important to them to know his intentions.  What would he do with royal power?  If he should succeed to the throne of David, what action would he take towards their treasured faith?


The Context

An honest examination of the entire Sermon shows Jesus to be making changes to the Law.  The repeated formula, You have heard that it was said . . . but I say unto you . . . leaves no uncertainty.  The fact, mentioned above, that the multitudes who heard him were shocked confirms that he was making changes - shocking changes!

Yes, he began with direct references to "the Law and the Prophets" but then at some point he departed from that to begin announcing his amendments.  Verse 5 is that point:


The evangelist did not make the transition obvious, but on examination we can see that  these least commandments  refers to something beyond the Law and the Prophets.

His Intentions

Knowing their concerns, Jesus assured both the crowd and his disciples, who were yet new and untried, that he did not intend to abolish or destroy their precious heritage of the Law and the Prophets.  He intended, instead, to fulfill them:

He came to fulfill them!  But what does that involve?

Consider first what it does not involve.  His word is precise:
He does not intend to take anything away from the Law -- but this leaves open the clear intention to add to it -- to raise the bar.  If the Law delivered to Moses represents the will of the Father for his children, then it would be a perfect law that needs no amendments.  Does not it follow that the Law of Moses is inadequate?  The intention of Jesus is to make the necessary changes so that it will comply with the perfect will of the Father and so be a perfect law-- for His children.

He stated his intention to fulfill the Law and the Prophets.  The NT Greek here is a word with many related meanings depending upon context.  I find two primary definitions that are relevant. 


Both of these definitions apply.  Let us first look at No. 2 to see how it applies:

From this we conclude that both the Prophets and the Law include prophecy, and that this is what Jesus stated as his intention with regard to the prophecies of the Prophets and the Law.  Everyone understands that the prophets prophesied, but not all know that the law also has prophecy.  The books of the law consist of the first five books of the OT, termed the Pentateuch.  Here is one of its prophecies of the Law from Deut. 18, where we find the Lord speaking to Moses and saying,
Jesus is that prophet, and so he fulfilled that prophecy of the law.  We can rest assured that he fulfilled prophecy from both the prophets and the law, making real what they had promised.  His intention was  to fulfill the prophecies of both the Law and the Prophets.  It is as he said:

This word, fulfill, also means to complete or make perfect (No. 1 above).  The prophecies of the prophets were complete within themselves as prophecy, as also the prophecies of the law.  But the law consisted primarily of commandments and, as such, it was his intention to complete them, to bring them to perfection.  He therefore, far from abolishing or destroying them, took them and made them perfect, such that they represented the Father's perfect will for his children in the world.  It follows that the law, as summed in the Ten Commandments, is not perfect and does not express the Father's will for his children.

The leaders of the Jews, determined to keep the law as it was delivered, nevertheless found that it was too difficult for them; they had therefore taken actions designed to relax the law, making it easier to keep.  The Sabbath law and the command to honor father and mother are cases in point, according to which Jesus rebuked them. 

His intention was to do the very opposite: to take the law as he found it and raise the bar until it truly represented the will of the Father for his children on the earth.  He took nothing away, but he definitely made additions.


How Jesus Raised the Bar

The bulk of the Sermon consists of new commandments according to which Jesus revised the Law of Moses -- by raising the bar, not by taking anything away.  He specified this as his intention six times, beginning at verses 5:21, 27, 31, 33, 38 and 43.  In each case he followed this or a similar formula:

We examine just one incident here (Matthew 5:21f):

Thus he raised the bar for the Sixth Commandment of the Decalog, "You shall not kill."  There follows a statement concerning the consequences for all who do not comply with the Sixth Commandment as amended!  Six times in Chapter 5 he raised the bar by direct revisions to the Law, not only of the Decalog, but also departing to other areas of the Law of Moses.  The purpose for these changes is stated in 5:48:

Now, do you understand why the crowd was shocked?  Jesus raised the bar to the very top notch, commanding his disciples, who are born from above and have become children of God, to be like God.  It is nothing less than this amended set of commandments to which the Sermon refers, beginning at verse 19 where he speaks of these commandments.   This defines these words of mine that are referenced in the Parable of the Two Builders at the end of the Sermon.  They comprise the perfect law. 

If we obey, we will be complete as our Father is complete.  If we do not obey, but find various ruses by which we set aside or relax these commandments, we are building on the sand.


Conclusion: Until John

The Law and the Prophets, as Jesus found them in Israel, and as they continue in Judaism and Christianity, had a termination point in relation to divine authority.  Here it is, clearly expressed by the Lord:

Moses delivered the Law; Jesus delivers the gospel of the kingdom and the Law of the Kingdom that amends and supersedes the Law of Moses.  If there were any doubt whatsoever as to the Lord's intention -- to supersede Moses -- the Lord's words from the Fourth Gospel puts it to rest.

Moses was but a servant, who as a servant received and delivered a servant law designed to guide the ancient servants of God.  Jesus is the Son who, as a son, received and delivered the law designed to guide the children of God in every age.  He became and remains our law giver, whose commandments are recorded in the gospels, and especially in the Sermon on the Mount.