What exactly is the significance of the Old Testament for us Christians (other than to point towards Jesus Christ)? How does the Old Covenant apply to someone under the New Covenant (if at all) in daily life?
Thank you for writing Probe Ministries. You ask some very good questions!
As to your first question, “What exactly is the significance of the Old Testament for us Christians,” I would probably want to say the following. First, the OT teaches us a number of crucial doctrines which are essential for Christianity. These include creation (Gen. 1-2), the fall of man (Gen. 3), the promise of a Deliverer (Gen. 3:15, etc.), the holiness of God (Leviticus), the need for a substitutionary blood sacrifice (Leviticus), the essential requirement of faith in God and His promises (Gen. 15:6), and God’s discipline of His wayward people (seen throughout the OT). We also learn a great deal about God’s interactions with people in the past (see 1 Cor. 10:6 in context), as well as His plans for the future. The wisdom literature and poetry (Job, Psalms, Proverbs, Ecclesiastes, and Song of Solomon) are, for the most part, timeless. They include wise advice on getting along successfully in the world, in relating to both God and our fellow man, as well as offering us examples of how to approach God in prayer and worship. Of course, as you said, its primary importance is to point us to Jesus Christ, the promised Messiah and Savior of the world. Finally, it’s interesting to note that in passages like 2 Tim. 3:14-17 and 2 Peter 1:20-21, the “Scripture” which is in view is primarily the OT. This is so because the NT was still in the process of being written. And it wouldn’t exist in its present form (i.e., 27 books bound together and recognized by the church as authoritative in matters of faith and practice) for a few centuries.
In your second question you ask, “How does the Old Covenant apply to someone under the New Covenant (if at all) in daily life?” First, let me point out that there are many moral commandments which are the same under both covenants. In fact, nine of the Ten Commandments are repeated and enjoined upon believers in the NT (all but the Sabbath day observance). Thus, there is clearly some continuity between the two covenants. However, there are also some important differences. For example, the dietary laws set forth in passages such as Leviticus 11:1-47 and Deuteronomy 14:1-21 were temporary laws given by God only to Israel. These laws are not applicable to Christians today under the terms of the New Covenant. This is not only made clear in Peter’s vision, recorded in Acts 10:9-16, but it is stated explicitly by Christ Himself in Mark 7:14-23. Notice in particular what Jesus says in vv. 18-19. In part, this text reads, “Do you not understand that whatever goes into the man from outside cannot defile him; because it does not go into his heart, but into his stomach, and is eliminated?” Then notice the parenthetical statement which concludes this verse: “Thus He declared all foods clean.” In other words, the dietary restrictions given by God to Israel have been nullified. Christians today are not bound by such laws. Today, the Old Covenant under which Israel operated is obsolete (Hebrews 8:13). Thus, while some of the moral commandments of the Old Covenant are reiterated for us in the New Covenant, strictly speaking, I do not believe that Christians are obligated to any of the duties or requirements of the Old Covenant. After all, the Old Covenant has been done away with by God Himself. Thus, any obligations that apply to us are repeated for us under the terms of the New Covenant. The New Covenant not only tells us how to live pleasing to God, etc., it also provides the means (through the indwelling of God’s Holy Spirit) to live consistently with it (as we walk in faith relying on the power of God’s Spirit).
In the New Testament, the book of Hebrews has a great deal to say about this New Covenant. In an article on “Covenant,” Trent Butler describes some of the special features of the New Covenant as related in the book of Hebrews:
“The emphasis is on Jesus, the perfect High Priest, providing a new, better, superior covenant (Heb. 7:22; 8:6). Jesus represented the fulfillment of Jeremiah’s new covenant promise (Heb. 8:8, 10; 10:16). Jesus was the perfect covenant Mediator (Heb. 9:15), providing an eternal inheritance in a way the old covenant could not (compare 12:24). Jesus’ death on the cross satisfied the requirement that all covenants be established by blood (Heb. 9:18, 20) just as was the first covenant (Ex. 24:8). Christ’s blood established an everlasting covenant (Heb. 13:20).” (Holman Bible Dictionary, gen. ed. Trent C. Butler [Tennessee: Holman Bible Publishers, 1991], 312)