If you look at the ideas and statements that immediately follow the meta-comments, you will see that these are Jesus’ key principles or conclusions. They communicate the point that he is trying to make in that section of his teaching. In 5:17, he has just stated that he did not come to abolish the law or the Prophets, but to fulfill them. Verse 18 reinforces this by the declaration that not even the smallest jot or tittle of the law will pass away until it is all accomplished. Notice also that some