I teach Old Testament for a living, so of course I’m biased toward it. But I think there are some other (at least four) really good reason to preach Christ—the cornerstone of our faith—from the Old Testament if we are to fulfill the mandate to preach the whole counsel of God (Acts 20:27).
1. Jesus taught that the Old Testament pointed directly to him.
That was his message on the Emmaus Road, and that was his message long before his resurrection from the dead. For example, in the parable of the Rich Man and Lazarus, when the rich man asks Abraham send Lazarus to warn the rich man’s five brothers so they could avoid his fate, Abraham responds by telling him that “They have Moses and the Prophets; they should listen to them. . . . If they didn’t listen to Moses and the prophets, they will not be persuaded if someone rises from the dead” (Luke 16:29, 31). In addition, Jesus condemned his interlocutors because “You pore over the Scriptures because you think you have eternal life in them, yet they testify about Me” (John 5:39 HCSB). We would do well to preach the Scriptures in accordance with Jesus’s testimony that the Old Testament testified to him and his work.
2. The apostles preached Christ from the Old Testament.
After all, the Old Testament is the Scripture of the apostles. Just read Peter’s Pentecost sermon, which utilizes Pss 16; 110; and Joel 2 as its base text. Paul also preached Christ from the Old Testament, as passages such as Acts 13 and Acts 17 indicate. And the Ethiopian eunuch was converted after Philip explained to him the meaning of Isaiah 53.
3. Preaching Christ from the Old Testament helps the church avoid moralism.
That is, when we preach Christ from the Old Testament, it moves the church beyond regarding the Old Testament as a series of stories that features men and women whom we should and should not emulate. Moralism is a somewhat common way to preach the Old Testament that goes something like this. In a sermon series on, for example, Abraham, a preacher could say that Abraham was a man of faith; he left his homeland, nearly sacrificed his son Isaac, and God made an everlasting covenant with him. The congregation should therefore try to be like Abraham. On the other hand, the preacher could in the next sermon look at the failures of Abraham: Abraham sinned against God by lying about his wife, Sarah. Christians should not lie and therefore we should not emulate Abraham.
Of course, such sermons are not entirely bad. The narratives of the Old Testament were written to encourage us to faithfulness and warn us of unfaithfulness. Paul says in Romans 15:4, “For everything that was written long ago was written to instruct us, so that we might have hope through the endurance and encouragement that the Scriptures give us.” And in 1 Corinthians we read in reference to the wilderness generation that “. . . these things became examples for us, so that we will not desire evil things as they did” (1 Cor 10:6) and “. . . these things happened to them as examples, and they were written as a warning to us, on whom the ends of the ages have come” (1 Cor 10:110). In that same chapter Paul lists several imperatives for the Christians at Corinth (and us today), including avoiding idolatry, sexual immorality, grumbling, and testing Christ.
Thus, we can and should point out Christians shouldn’t lie and that we should be people of faith. In fact, Paul points to Abraham for this very reason (see Rom 4). But there is much more to the Abraham narratives than a simple “do this; don’t do this.” Preaching Christ will ensure that we do not gloss over the true import of the Abraham narratives: the faithfulness and goodness of Yahweh, how he expects his people to respond to him, and what it means to be a follower of Yahweh.
4. We should preach Christ because it will help the church avoid legalism.
This was a common issue for Israel, the early church, and for us today. Simply stated, legalism is the view that all God demands from his followers is a rigid application of his laws to their lives. Such a view misses completely the heart of both the Old Testament and the New Testament, and it ultimately led to the exile of the people of Israel and later Jesus’s fierce condemnation of the Pharisees. Legalism places faith in a person’s ability to keep God’s law instead of placing faith in Christ, the fulfillment of that law.
In the book of Galatians Paul takes up this issue, arguing forcefully that the gospel plus law keeping is in fact no gospel at all. What God requires, instead of slavish devotion to the law, is faithfulness to the Lord that develops as a response to his faithful love. As Paul states, “Christ has liberated us to be free. Stand firm then and don’t submit again to a yoke of slavery [that is, supposed righteousness gained through legalism]” (Gal 5:1). Now that such freedom has been attained, we must not “use this freedom as an opportunity for the flesh, but serve one another through love. For the entire law is fulfilled in one statement: Love your neighbor as yourself” (Gal 5:13–14). Thus, there is law keeping in one sense, namely that followers of Christ will love each other (and thus keep the law; see Matt 22:37; Luke 10:27), but this law keeping results from a love for God, not a desire to earn salvation through keeping the law.
Paul’s treatise on law keeping in Galatians shows that preaching Christ helps us to rightly understand the Old Testament and therefore to avoid the legalism that had ensnared the Galatians. Returning to Abraham, a preacher could rightly preach the importance of obedience to God from the Abraham narratives (in fact, James does just this; see Jas 2:14–26). However, such a sermon can easily veer into legalism, as someone might say, “In order to please God, I must obey God like Abraham did. If I obey in all things, then God will love me, be pleased with me, bless me, etc.” A Christocentric (and thus theocentric) sermon will also emphasize the importance of Abraham’s obedience, but it will focus especially on the fact that Abraham’s obedience springs from God’s faithfulness to him and the relationship that resulted therefrom.
The person hearing a sermon that focuses on God’s faithfulness to Abraham may also walk away thinking, “In order to please God, I must obey God.” But that thought will (hopefully) be followed with, “God is pleased with me already because of the sacrifice of Christ. I can now obey God because of the right relationship Jesus secured on the cross.” The physical outcome may look similar (both people obey God), but the Christocentric sermon will lead us to obey God because God has already established a relationship with him, not in order to establish that relationship through law keeping.