Jesus’ Use of the Law in Scripture
Much has been debated about the fulfillment of the law—questions toward Jesus changing the law present as fact. In Matthew 5:17-19, Jesus refers to fulfilling the law, not getting rid of it, or disregarding its importance, but looking to Christ for that fulfillment. DeYoung mentions that Jesus taught a deeper understanding of the law and that “they should come to Christ in obedience to find cleansing and purity.“
The authority is no longer in the Scripture itself. While the Scripture is still holy, Jesus’ authority as God is the way of new understanding. The BKC offers that the people are given a clear responsibility. The righteousness they seek via the Pharisees isn’t sufficient for entrance into the kingdom Jesus was offering by his authority. In Matthew 9:8, the HCBC notes that “there is also a sense in which the Father gives his power.
In Matthew 12:38-42, Jesus refers to Jonah and his being swallowed by the fish, not to be seen for three days. Jesus treats all accounts of high drama in the Bible as historical fact. In Jesus’ view, all Scripture is the word of God and to demonstrative as actual history. This reference helps to illustrate and clarify that the Bible’s authority as God-breathed is accurate. As DeYoung notes, the followers of Christ are not to think of Jesus as the judge of Scripture. As by word and deed, Christ endorses the authority of the entire Bible. The sign-seekers are refused another miracle as the authority of Scripture as Jesus knew they had already decided to reject him.
In Matthew 19:4-5, the Pharisees sought to test Jesus’ knowledge of the law when considering the issue of divorce. Jesus offers a reference from Genesis 2:24 to show that the bond of marriage is a lifelong commitment and that the authority of Scripture is the authority of God. As DeYoung mentions, “This is the essence of Jesus’s doctrine of Scripture and the foundation for any right understanding of the Bible.”  Jesus is always consistent in his confirmation of Scripture as being the word of God. He may clarify or refute wrongful interpretations of Scripture but constantly affirmed the infallibility of the Bible.
I believe Matthew 5:17-19’s reference is the best example of what Jesus wished to communicate regarding his authority. Jesus fulfills the Jewish laws, but people had not yet understood that he was that fulfillment. Only by recognizing Jesus’ authority as God could non-believers (and even believers) understand the significance of this fact. First-century Christians had to unlearn their thinking on the law.
 David S. Dockery and Broadman & Holman Publishers, eds., Holman Concise Bible Commentary: Simple, Straightforward Commentary on Every Book of the Bible, Holman reference (Nashville, Tenn: Broadman & Holman Publishers, 1998), 147.