It is unfortunate that so many who come to Christ for salvation are misled by false teaching that claims that the Mosaic Law and the words of the Old Testament Prophets are worthless to the Christian. This false teaching leads to a heresy that teaches that the Christian is free from the obligations of obeying God's Law.
Jesus addresses this false understanding of God's Word and the Gospel. In this section of the Sermon on the Mount, Jesus makes it clear that His message is not one of Antinomianism (anti-law) but instead is a proclamation that the Law and the Prophets were right and that He (Jesus) fulfills all that was taught and prophesied in the Old Testament. The teaching of false prophets argue that the Christian is no longer obligated by legalism or standards of morality. But instead, Jesus clearly calls all who are citizens of the Kingdom of Heaven to obey God's Law as a matter of willing desire instead of overburdened obligation.