A key part of Jesus’ teachings was to show the inadequacy of the Law for achieving righteousness.
One day he commented, “You have never murdered anyone? Never violated the 6th commandment? Never broke that law? Well, if you think someone is an empty-headed fool and you say that out loud then you are in danger of hell.”
“And you have never had a physical adulterous relationship? You have never broken the 7th commandment? Well, if you have ever had a lustful thought, then you’ve committed adultery in your heart and that’s the same thing.”
And some religious people in that crowd heard those teachings, and just like religious, well-meaning people who hear them today, they said, “Hmmm. Jesus just gave us some new rules. We need to follow those rules also.”
But what was Jesus really doing? He was showing them the impossibility of achieving righteousness by following a law system of human works.
Jesus was not giving new laws; he was letting the Law do its work. He was letting it condemn self-righteousness so that his hearers would realize their need for the righteousness he would offer.