I have been at some pains to say that the most powerful, God-blessed and divinely approved witnessing for the Christian is the witness of a life of obedience to the will of Christ.

I insisted on the fact that the key to Christian witnessing is I Peter 3:15: “But sanctify the Lord God in your hearts: and be ready always to give an answer to every man that asketh you a reason of the hope that is in you with meekness and fear.” Peter is talking about good works as a witness. Good works are implied in that absolutely necessary prerequisite for giving a defense of our hope: sanctify the Lord God in your hearts.

Good works are also implied in the fact that people ask us a reason for our hope. They will not ask if they do not see something different—that is, see good works, in us.

But good works are also specifically mentioned in Jesus’ remarks about letting our light shine before men (Matt. 5:14-16); good works are mentioned in the Heidelberg Catechism as being necessary for the Christian to do so that “by [our] godly conversation (life-style), others may be gained to Christ” (HC 32/86).

Not, in the first place, is speech important; one’s life is the crucial thing.

Because genuine (not frothy, sentimental, outward) good works are the stream that flows from doctrine, the prerequisite of witnessing is a firm and correct knowledge of the truth of Scripture. People make a serious mistake when they complain from the pew that preaching is too doctrinal and not practical. The cry is heard so often that it makes ministers uncomfortable. I am not saying that faithful ministers are never practical in their preaching. Surely, we all agree that a minister ought to be careful to show God’s people just how the truths of Scripture apply to concrete situations in life. But to show how truth applies to life means, it seems clear, that one has to talk about the truth and preach the truth.

This is quite sobering. I am convinced that the church of Ephesus received from the Lord such a sharp warning about the imminence of the demise of the church that had lost its first love, because in Ephesus could no longer be found a love for the truth (Rev. 2:1-7). That love for the truth was Ephesus’ first love.

The Lord makes clear that Ephesus was strong in fighting heresy and standing for the truth revealed to them by Christ. They even censured heretics and excommunicated them when these heretics did not repent. But the trouble was that the people had no love for the truth.

When Paul wrote a letter to the church in Thessalonica, he warned them about the Anti-christ and described in one of Scripture’s clearest teachings about Anti-christ that those who followed this man of sin would be punished terribly by a strong delusion so that they believe the lie and are damned (II Thess. 2:1-12). But this dreadful punishment is sent on them because “they received not the love of the truth” (verse 10).

A head full of cold and abstract knowledge of the truth will not do for witnessing. Knowledge of the truth must be present in a witness—of course; but more is needed. He must love the truth. That is something more.

Witnessing is less than the foam on top of a glass of coca-cola if it is only a friendly hand sake and a white-toothed smile accompanied by some reference to Jesus as one’s personal Savior, when it all is a gloss over an ignorance of Scripture and the truth revealed in it. And witnessing means nothing and is fundamentally impossible when it covers a shameless disregard for the truth.

If I do not love my wife passionately and exclusively, I am not going to defend her good name when it is attacked. If I do not love the church of Christ of which I am a part, I will not come to the defense of the denomination and congregation when it is slandered. I love my wife because she is what she is. I love God because he is what he is. I love the truth because the truth is God. And a defense of what we love is, after all, what witnessing is all about.

We gain such a knowledge of and love for the truth in church on Sunday when the minister preaches, in catechism class when the shepherd of the flock instructs the lambs and young sheep, when we spend time at home reading books that tell us of the truth, and when we spend part of the day in devotions. How can one know the truth and love it, without these spiritual exercises? I say it again: How can anyone witness when he is remiss and unfaithful in these basic things?

So, if we love the truth we are faithful to the truth—as a man is faithful to his wife because he loves her;—and because we are faithful to God because we love him. Faithfulness to God is faithfulness to his truth. That is the way it is. One cannot change that no matter how one tries. Preparation for witnessing is not a special class on how to meet and talk to others; it is rather a class in Reformed doctrine.

Is this so difficult to understand? It ought not to be. The antithesis means, among many other things, that we stand for the truth over against the lie. “Let your light so shine among men…, Jesus says. The truth is that light! The lie of this world is darkness. We even speak of the light of the truth and the darkness of the lie. Let us then take that seriously.

The trouble is not so much that we do not know these ABCs of life; the trouble is that we do not want to take the time to learn the truth. It seems to us to demand effort that lies beyond our energies, and the knowledge of the truth seems to require a concentration on boring things when life’s pleasures are all out there with our buddies beckoning with enticing words to come and have some fun once. There is little sense in talking about witnessing when such an attitude of indifference to truth clamps its icy fingers around our throats.

The questions we ought to be asking ourselves before we become overly eager to witness are these: Do I know the heritage of the Reformed faith? Am I acquainted with the distinctives of Protestant Reformed doctrine? Can I defend the truth of sovereign grace against Arminianism in all its forms? Creationism against the deadly lie of evolutionism? Do I love that truth? That is, am I willing to give up everything I have for the sake of the truth?—as countless martyrs have done before me? Does that truth mean so much to me that I will die for it? Love of the truth is love for God, is it not? If I love him, I want to be faithful to him in all my life.

Then, and then only are we ready to become witnesses.