When we read Jesus’ Sermon on the Mount we find that he not only acknowledges the Law of Moses, but makes obedience seemingly impossible.  So we need to fully examine what Jesus is saying here in order to more fully understand how it affects us. 

There was a distinction between the Law of Moses and the commandments given by Jesus in his sermon. The law was given to Moses in the form of crime and punishment.  If you commit this crime, you will suffer this punishment. The emphasis was on the committing of the crime rather than what drove man to commit the crime.  So the law dealt more with the act of disobedience.  It was written upon stone tablets in order to give us the impression that it was very rigid and unyielding.  God didn’t seem to consider why we broke his law, but just that we broke it.

Paul teaches us in Romans that Jesus’ version of the law fulfills what was spoken by the prophet Jeremiah by explaining that the law is now written upon our hearts.  

Romans 2:15 (ASV)
¹⁵in that they show the work of the law written in their hearts, their conscience bearing witness therewith, and their thoughts one with another accusing or else excusing them);

Jeremiah 31:33 (NIV)

“This is the covenant I will make with the people of Israel after that time,” declares the LORD. “I will put my law in their minds and write it on their hearts. I will be their God, and they will be my people.

Jesus’ interpretation of the law dealt more with the internal causation of the crime than the crime itself giving us the idea that he believed the act of the crime began deeper within the heart of man than simply a thoughtless reaction to circumstances.  In other words, Jesus personalized the law whereas Moses depersonalized it.  We could say that Jesus spoke not simply as one who knew the law, but was a personalization of it in himself. He was, in fact, the law (Word) in the flesh. 

But what advantage is this to mankind that God would do such a thing? It was so that man could see the holiness of God more clearly and through this new vision of the law would feel the judgement of God more deeply since it was aimed directly at the heart.  So sin was not simply the committing of the act, but that sin lived within the hearts of men.

But there is also another reason that God manifested the law in Christ.  It was so that man could see the holiness of God in human form through the obedience of Jesus and relate to it at the highest level possible for man—through love. Yes, it is through love that we see the commandments of Christ. For it is through love and only through love that we can truly obey them.  For love is at the root of obedience. 

Did you ever wonder how we know that we are truly a Christian?  Well, John gives us the answer in his 1^st letter:

1 John 2:3-6 (KJV)
³And hereby we do know that we know him, if we keep his commandments.
⁴He that saith, I know him, and keepeth not his commandments, is a liar, and the truth is not in him.
⁵But whoso keepeth his word, in him verily is the love of God perfected: hereby know we that we are in him.
⁶He that saith he abideth in him ought himself also so to walk, even as he walked.

The connection between love and obedience is clear in the above scripture.  Our love for God is perfected (completed) by our obedience.  For obedience without love is nothing more than self-righteousness. We will see the importance of love and Jesus’ commands as we read through the next verses of his sermon.