Paul writes to the church at Rome, “For everything that was written in the past was written to teach us, so that through endurance and the encouragement of the Scriptures we might have hope” (Rom 15:4). Here Paul refers to the Old Testament scriptures and emphasizes their importance for Christian communities. In 2 Timothy 3:16-17, Paul is referring primarily to the Old Testament scriptures when he writes, “All Scripture is God-breathed and is useful for teaching, rebuking, correcting and training in righteousness, so that the servant of God may be thoroughly equipped for every good work.” The apostle Paul is writing to Timothy, who is a leader in the early Christian church, instructing him concerning the relevance of the Old Testament scriptures to the life and ministry of the church. In Paul’s view, the Old Testament scriptures are the words of God and so does not cease in its relevance. This relevance extends to the present day; however, this is not to say that there are not temporal elements of the Old Testament. Gordon Fee and Douglas Stewart rightly point out that “all of the Old Testament law is still the Word of God for us even though it is not still the command of God to us.” There are Old Testament laws, commands and covenant obligations that were important and vital for the Jews and are not to be applied to the Christian church, but this is not license to ignore the Old Testament because there are also universal and permanent elements that exist within its pages. Martin Davie writes,
The task of the Christian reader of the Old Testament is thus to discern how in any given part of the Old Testament the good that is willed by God for all people at all times and everywhere is revealed in and through what is contingent and to think how this universal good applies to us as Christians today in our own particular contingent historical situation.
Moreover, God wants people to read and understand the Old Testament because he reveals himself through it. A robust doctrine of God is developed throughout the Old Testament revealing his attributes, character and relationship with humanity. This Old Testament theology is the foundation for the New Testament. Readers of the Old Testament encounter many theological themes that continue into the New Testament (i.e. holiness of God, sin of man, sacrifice, reconciliation, redemption, etc.). Thus, the Old Testament prepares readers for the New Testament. The New Testament was never meant to stand alone because the doctrines presented therein are supplemental and complementary to the doctrines in the Old Testament. “Christianity is incomprehensible without Judaism, and the authenticity of the Second Testament depends on its congruity with the First.”
Another response addressing the relevance of the Old Testament for Christians is christological in nature. Jesus states, “Do not think that I have come to abolish the law or the prophets; I have not come to abolish them but to fulfill them. I tell you the truth, until heaven and earth disappear, not the smallest letter, not the least stroke of the pen, will by any means disappear from the law until everything is accomplished” (Matt 5:17-18 NIV). Also, Jesus comments to the Jewish teachers of his day, “You study the Scriptures diligently because you think that in them you have eternal life. These are the very Scriptures that testify about me” (John 5:39 NIV). The Old Testament is a collection of writings that are filled with prophecies about a future messiah. From beginning to end (Gen 3:15 to Mal 4:1) the Old Testament points to the life and ministry of Christ. The early Christian church regularly set their focus on the Old Testament prophecies concerning the Christ in order to understand God’s salvation in light of Jesus’ life and ministry. They found that Jesus fulfilled all the unfilled messianic prophecies and satisfied all the unsatisfied longings for redemption.
In order to have a proper Christology in the present day, individuals should heed the words of Jesus and follow the example of the early church and turn to the Old Testament. A better understanding of the messianic promises located in the Old Testament will help Christians better appreciate all that Jesus achieved in his life and ministry. The apostle Paul explains to the church at Corinth that the Israelites have a veil over their hearts concerning to the deeper truths of God within the Hebrew Scriptures, but for those who are in Christ the veil has been lifted and the Holy Spirit leads them into all truth, and they are set free being transformed into the likeness of Christ (2 Cor 3:13-16). Therefore, Christians should take advantage of this removing of the veil from their hearts and explore the Old Testament to the glory of God.
[1 Gordon D. Fee and Douglas K. Stuart, How to Read the Bible for All Its Worth: a Guide to Understanding the Bible (G.K. Hall, 1993), 153.  Martin Davie, Our Inheritance of Faith: a Commentary on the Thirty Nine Articles (Gilead Books Publ., 2013), 278.  W. H. Griffith Thomas. The Principles of Theology: an Introduction to the Thirty-Nine Articles (Wipf and Stock, 2005), 141.  Ibid., 136.