Reformed theology understands that God has chosen to relate to us by means of covenant — a relationship established by a promise. There are two divine covenants, namely the covenant of works and the covenant of grace. Witsius wrote: “[The law] served the covenant of works of old: and still it serves the covenant of grace.” Obedience to the law became the condition of what was promised in the covenant of works – do this and live, a covenant broken by our first parent’s sin. God’s redemptive way of relating to his people is through the covenant of grace in which the law still has an important place.
I was sitting across the table from my pastor when he asked what I thought the weakest part of his preaching was. As someone who is prone to a critical spirit I was hesitant to answer. But, at his prodding, I gave my opinion: “I think the weakest part of your preaching is that you’re scared to tell Christians what they need to do.” He responded by saying: “That’s a very fair observation.” He went on to admit that he’d rather tell people what Christ did for them than tell them what they need to do for Christ.
It’s a short anecdote but it illustrates what is often a perceived tension in preaching — the distinction between law and gospel. This distinction is important in Reformed theology. In his excellent book Conciliatory or Irenical Animadversions, Dutch theologian Herman Witsius helpfully defined the “strictest notion” of both words. He wrote: “The law signifies that part of the Divine word which consists in precepts and prohibitions, with the promise of conferring a reward upon them who obey, and threatenings of punishment to the disobedient.” He went on to say: “The gospel signifies the doctrine of grace, and of the fullest salvation in Christ Jesus, to be received by elect sinners by faith.” According to these narrow definitions we might say that law is command and gospel is promise.
The distinction between law and gospel finds its way into many questions — not the least of which is pulpit ministry. Martyn Lloyd-Jones once famously quipped that preaching the gospel faithfully will likely get you accused of being antinomian — that is, anti-law. But the reciprocal is true too. Faithfully preaching the law can get you accused of being moralistic or, what is sometimes called neonomian — making the gospel a new law. Neonomianism and antinomianism are significant threats to the truth of Jesus Christ. On the one hand, those who pervert grace to lawlessness are designated for condemnation (Jude 4, and Matthew 7:23, Titus 2:14, 2 Peter 3:17, and 1 John 3:4), and on the other hand those who undermine grace by works are also under a curse (Galatians 3:10, see also 2:16 and Romans 3:20, 28).
How should law and gospel relate in preaching? One simple answer might be to say that the law should be used to show us our need for Jesus — the law is preached in order to make hearers desire the promise of the gospel. To borrow the expression of the Apostle, that is a lawful use of the law. After all, this same Apostle said: “I would not have known sin except through the law. For I would not have known covetousness unless the law had said, ‘You shall not covet’” (Romans 7:7).
But this simple formula — preaching the law to preach the gospel — isn’t the only way that law and gospel should relate in the pulpit. Here, Herman Witsius is a great guide as he lays down several things that aid an understanding of preaching law and gospel.
First, while it’s true that law and gospel can be defined strictly, it’s also biblically true that they can be defined more broadly. Witsius says “all who are acquainted with theology” recognize a more extensive definition.