Whatever the specific meaning Jesus has for fulfillment in Matthew 5:17, the main point is that He is that fulfillment. I have not come to abolish; I have come to fulfill. This is His role and His purpose. The rest of Matthew goes on to confirm that emphasis. Jesus fulfills, and is the fulfillment, of all written in the Law and the Prophets.
As the New Testament unfolds, it becomes clear: Jesus fulfilled the Old Testament’s law, predictions and promises. Thus, he brought the law to its successful and intended conclusion.
For Christ is the end of the law for righteousness to everyone who believes. (Romans 10:4)
In saying this, Paul sums up what he has made clear step by step in his letter (Romans 3:20, 28; 4:14-15; 6:14; 7:6; 8:3). After building a full understanding, Paul then declares, “Christ is the end of the law.” That Greek word for “end” is telos, which has to do with finishing, reaching a goal, fulfilling a purpose. As one rendition says, “For Christ has accomplished the whole purpose of the law.” Here is a case, like completion of the terms of a contract, where fulfillment of the purpose results in a natural end.