We come today to one of Jesus’ most complex teachings as it discusses the life and role of the old covenant Law. This is a much-debated topic, and thus we will carefully draw conclusions that accord well with the entirety of Scripture.
Jesus discusses the Mosaic law at this point in the Sermon on the Mount to prevent His disciples from misunderstanding the teaching that follows. Our Lord is about to correct the interpretations of the Pharisees (Matt. 5:21–48), who are beloved by the common man. The people equate these traditions with the Law itself, and to correct them is to violate God’s Word in the eyes of the people unless Christ makes His intention clear beforehand.
Verses 17–20 tell us that breaking our Father’s commands is far from Jesus’ mind. His work is not “to abolish the Law or the Prophets…but to fulfill them” (v. 17). The Messiah’s coming does not render the Old Testament obsolete. “To fulfill” is not to dissolve the authority and application of the old covenant revelation; rather, “to fulfill” means to fill up the Law’s intent and show the goal to which it leads. Jesus is saying that He achieves the purpose of the Law and the Prophets in the inauguration of the kingdom in His life and ministry and in its consummation at His return. The Law is valid under the new covenant when used “lawfully” (1 Tim. 1:8), but it cannot be followed rightly apart from Christ.
Seeing that Jesus fulfills the Law helps us see its relation to us today. Christ does not abrogate the Law in the sense that certain parts of it are cast off completely. For example, the new covenant does not end God’s demand for atonement. But we do not sacrifice animals, because Jesus, who is the end of the sacrificial system, has come. Our Lord, as the goal of the sacrifices, inaugurated the kingdom in His death, and now we obey our Father’s demand for atonement by approaching Him through the shed blood of Christ (Heb. 10:1–18).
On the other hand, the goal of what is often called the moral law (WCF 19) is a heart set apart to obey God joyfully and without hesitation (Deut. 30:6). Christ has begun this work in us (Heb. 8:13), but He will not finish it until He consummates the kingdom (9:27–28). Until then, the Law’s ethical norms are fully binding.
The distinction between the civil, ceremonial, and moral laws of the Mosaic code is not so clear on the pages of Scripture. Nevertheless, the distinction is a helpful tool for applying this law to our lives today. We study the Mosaic law to learn what God would have us do in Christ. This law has been written on our hearts thanks to the Holy Spirit, though we still certainly struggle doing it. Make sure to spend time each week in study of the law of God.