Doubt is a major problem for Christian believers, but we are very reluctant to admit it. We are reluctant, of course, to admit many spiritual problems, like anger, anxiety, and envy. But doubt may be the hardest to admit, because doubt seems to be the opposite of faith itself. The Heidelberg Catechism Q 21, says that faith is “an assured confidence”. How can there be any doubt in an “assured confidence” if salvation itself is “by faith” (Ephesians 2:8)? If doubt is a lack of faith, how can a doubter be saved at all?

The Bible itself presents doubt largely negatively. It is a spiritual impediment, an obstacle to doing God’s work (Matthew 14:31; 21:21, 28:17, Acts 10:20, 11:12, Rom. 14:23, 1 Tim. 2:8, Jas. 1:6). In Matthew 14:31 and Romans 14:23, it is the opposite of faith and therefore a sin. Of course, this sin, like other sins, may remain with us through our earthly life. But we should not be complacent about it. Just as the ideal for the Christian life is perfect holiness, the ideal for the Christian mind is absolute certainty about God’s revelation.

We should not conclude that doubt is always sinful. Matthew 14:31 and Romans 14:23 (and others passages) speak of doubt in the face of clear special revelation. To doubt what God has clearly spoken to us is wrong. But in other situations, it is not wrong to doubt. In many cases, in fact, it is wrong for us to claim knowledge, much less certainty. Indeed, often the best course is to admit our ignorance (Deuteronomy 29:29; Romans 11:33-36). Paul is not wrong to express uncertainty about the number of people he baptized (1^st Corinthians 1:16). Indeed, James tells us, we are always ignorant of the future to some extent and we ought not to pretend we know more about it than we do (James 4:13-16). Job’s friends were wrong to think that they knew the reasons for his torment, and Job himself had to be humbled as God reminded him of his ignorance (Job 38-42).

So although Scripture presents doubt negatively, as a sin, as a spiritual impediment, it is not a sin that invalidates a Christian’s profession of faith. It is inconsistent with faith, as all sin is. But like other sins, it may remain with us for many years. A believer will struggle against it, but may not gain total victory over it until he or she enters into glory.

But how are we to struggle against the doubts that beset us? First, we should be honest before God about our doubts. In Mark 9:24, a man wanted Jesus to heal his son, but when Jesus told him the importance of believing, the man admitted to Jesus, “I believe; help my unbelief!” Jesus honored the man’s honesty and healed his son. Often writers of the Psalms express questions to God, questions that indicate some level of doubt about God’s promises. In Psalm 73, for example, Asaph questions the justice of God’s dealings with the wicked:

But as for me, my feet had almost stumbled, my steps had nearly slipped. For I was envious of the arrogant when I saw the prosperity of the wicked. 

Later in the Psalm, Asaph is reassured; but there is also Psalm 88, in which there is no explicit reassurance. It is right for us to express our doubts to God and ask Him to restore our faith. For ultimately, only He can deal with them. The final solution for doubt is God’s supernatural work in our heart, enabling us to understand His ways and enabling us to praise Him even when we do not understand.

But additionally, it is possible even in this life to gain some victory over our doubts. I have said that absolute certainty is the appropriate (if ideal) response to God’s special revelation. How can that be, given our finitude and fallibility? How is that possible when we consider the skepticism that pervades secular thought? How is it humanly possible to know anything with certainty?

First, it is impossible to exclude absolute certainty in all cases. Any argument purporting to show that there is no such certainty must admit that it is itself uncertain. Further, any such argument must presuppose that argument itself is a means of finding truth. If someone uses an argument to test the certainty of propositions, he is claiming certainty at least for that argument. And he is claiming that by such an argument he can test the legitimacy of claims to certainty. But such a test of certainty, a would-be criterion of certainty, must itself be certain. And an argument that would test absolute certainty must itself be absolutely certain.

So skepticism—the view that we can know nothing with assurance—necessarily fails, for the skeptic is never skeptical about his skepticism. And if he claims assurance about his skepticism, he is no longer a skeptic.

In a biblical view of knowledge, God’s word is the ultimate criterion of certainty. What God says must be true; for, as the letter to the Hebrews says, it is impossible for God to lie (Hebrews 6:18; compare Titus 1:2 and 1^st John 2:27). His Word is Truth (John 17:17; compare Psalms 33:4, 119:160). So God’s Word is the criterion by which we can measure all other sources of knowledge.

When God promised Abraham a multitude of descendants and an inheritance in the land of Canaan, many things might have caused him to doubt. He reached the age of one hundred without having any children, and his wife Sarah was far beyond the normal age of childbearing. And though he sojourned in the land of Canaan, he didn’t own title to any land there at all. But Paul says of Abraham that “no distrust made him waver concerning the promise of God, but he grew strong in his faith as he gave glory to God, fully convinced that God was able to do what he had promised” (Romans 4:20-21). God’s Word, for Abraham, took precedence over all other evidence in forming his own belief. So important is this principle that Paul defines justifying faith in terms of it: “That is why [Abraham’s] faith was counted to him for righteousness” (verse 22).

Thus, Abraham stands in contrast to Eve, who (in Genesis 3:6) allowed the evidence of her eyes to take precedence over the command of God. Abraham is one of the heroes of the faith, who (according to Hebrews 11:13), “died in faith, not having received the things promised, but having seen them and greeted them from afar…” They had God’s promise, and that was enough to motivate them to endure terrible sufferings and deprivations through their earthly lives.

I would conclude that it is the responsibility of the Christian to regard God’s word as absolutely certain, and to make that word the criterion of all other sources of knowledge. Our certainty of the truth of God comes ultimately, not through rational demonstration or empirical verification, useful as these may often be, but from the authority of God’s own Word.

God’s Word does testify to itself, often, by means of human testimony and historical evidence: the “proofs” of Acts 1:3, the centurion’s witness in Luke 23:47, the many witnesses to the resurrection of Jesus in 1^st Corinthians 15:1-11. But we should never forget that these evidences come to us with God’s own authority. In 1^st Corinthians 15, Paul asks the church to believe the evidence because it is part of the authoritative apostolic preaching: “so we preach and so you believed” (verse 11; compare verses 1-3). Today, we learn about the “proofs” of the Gospel from the Bible, God’s authoritative Word.

But how does that Word give us psychological certainty? Even good arguments often leave us with psychological doubts. Christians sometimes make great intellectual and emotional exertions, trying to force themselves to believe the Bible. But we cannot make ourselves believe. Certainty comes upon us, as I said earlier, by an act of God, through the testimony of His Spirit (1^st Corinthians 2:4, 9-16; 1^st Thessalonians 1:5, 2 Thess. 2:14). The Spirit’s witness often accompanies a human process of reasoning. Scripture never rebukes people who honestly seek to think through the questions of faith. But unless our reason is empowered by the Spirit, it will not give full assurance.

So certainty comes ultimately through God’s Word and Spirit. The Lord calls us to build our life and thought on the certainties of His Word, that we “will not walk in darkness, but have the light of life” (John 8:12). The process of building, furthermore, is not only academic, but ethical and spiritual. It is those who are willing to do God’s will that know the truth of Jesus’ words (John 7:17), and those that love their neighbors, who are able to know as they ought to know (1^st Corinthians 8:1-3).

Secular philosophy rejects absolute certainty because absolute certainty is essentially supernatural, and because the secularist is unwilling to accept a supernatural foundation for knowledge. But the Christian regards God’s Word, illumined by the Spirit, as His ultimate criterion of truth and falsity, right and wrong, and therefore as the standard of certainty. Insofar as we consistently hold the Bible as our standard of certainty, we may and must regard it as itself absolutely certain. In this life we will do this imperfectly. All sin comes from our failure to trust God’s Word as our absolute standard. But we should rejoice that in God’s Word we have a firm basis for assurance of His truth. By the grace of Jesus Christ, we have a wonderful treasure, one that saves the soul from sin and the mind from skepticism.

Bibliography:

Frame, John M., Christianity Considered (Bellingham, WA: Lexham Press, 2018); The Doctrine of the Knowledge of God (Phillipsburg, NJ: P&R Publishers, 1987);The Doctrine of the Word of God (Phillipsburg, NJ: P&R Publishers, 2010); Nature’s Case for God (Bellingham, WA: Lexham Press, 2018).

Poythress, Vern, Knowing and the Trinity: How Perspectives in Human Knowledge Imitate the Trinity (Phillipsburg, NJ: P&R Publishers, 2018).

Van Til, Cornelius, A Christian Theory of Knowledge (Phila.: Presbyterian and Reformed Publishing Co., 1961); A Survey of Christian Epistemology (Phillipsburg, NJ: P&R Publishers, 1980).