Ask anyone today, "What is truth?" and you’re sure to start an interesting conversation. Try it on a university campus and you’re likely to receive laughter, scorn, and derision. The concept of truth has clearly fallen on hard times, and the consequences of rejecting it are ravaging human society. So let’s go back to the starting point and answer the question: What is truth?

One of the most profound and eternally significant questions in the Bible was posed by an unbeliever. Pilate—the man who handed Jesus over to be crucified—turned to Jesus in His final hour, and asked, “What is truth?” It was a rhetorical question, a cynical response to what Jesus had just revealed: “I have come into the world, to testify to the truth.”

Two thousand years later, the whole world breathes Pilate’s cynicism. Some say truth is a power play, a metanarrative constructed by the elite for the purpose of controlling the ignorant masses. To some, truth is subjective, the individual world of preference and opinion. Others believe truth is a collective judgment, the product of cultural consensus, and still others flatly deny the concept of truth altogether.

So, what is truth?

Here’s a simple definition drawn from what the Bible teaches: Truth is that which is consistent with the mind, will, character, glory, and being of God. Even more to the point: Truth is the self-expression of God. That is the biblical meaning of truth. Because the definition of truth flows from God, truth is theological.

Truth is also ontological—which is a fancy way of saying it is the way things really are. Reality is what it is because God declared it so and made it so. Therefore God is the author, source, determiner, governor, arbiter, ultimate standard, and final judge of all truth.

The Old Testament refers to the Almighty as the “God of truth” (Deuteronomy 32:4; Psalm 31:5; Isaiah 65:16). When Jesus said of Himself, “I am…the truth” (John 14:6, emphasis added), He was thereby making a profound claim about His own deity. He was also making it clear that all truth must ultimately be defined in terms of God and His eternal glory. After all, Jesus is “the brightness of [God’s] glory and the express image of His person” (Hebrews 1:3). He is truth incarnate—the perfect expression of God and therefore the absolute embodiment of all that is true.

Jesus also said that the written Word of God is truth. It does not merely contain nuggets of truth; it is pure, unchangeable, and inviolable truth that (according to Jesus) “cannot be broken” (John 10:35). Praying to His heavenly Father on behalf of His disciples, He said this: “Sanctify them by Your truth. Your word is truth” (John 17:17). Moreover, the Word of God is eternal truth “which lives and abides forever” (1 Peter 1:23).

Of course, there cannot be any discord or difference of opinion between the written Word of God (Scripture) and the incarnate Word of God (Jesus). In the first place, truth by definition cannot contradict itself. Second, Scripture is called “the word of Christ” (Colossians 3:16). It is His message, His self-expression. In other words, the truth of Christ and the truth of the Bible are of the very same character. They are in perfect agreement in every respect. Both are equally true. God has revealed Himself to humanity through Scripture and through His Son. Both perfectly embody the essence of what truth is.

Remember, Scripture also says God reveals basic truth about Himself in nature. The heavens declare His glory (Psalm 19:1). His other invisible attributes (such as His wisdom, power, and beauty) are on constant display in what He has created (Romans 1:20). Knowledge of Him is inborn in the human heart (Romans 1:19), and a sense of the moral character and loftiness of His law is implicit in every human conscience (Romans 2:15).

Those things are universally self-evident truths. According to Romans 1:20, denial of the spiritual truths we know innately always involves a deliberate and culpable unbelief. And for those who wonder whether basic truths about God and His moral standards really are stamped on the human heart, ample proof can be found in the long history of human law and religion. To suppress this truth is to dishonor God, displace His glory, and incur His wrath (vv. 19-20).

Still, the only infallible interpreter of what we see in nature or know innately in our own consciences is the explicit revelation of Scripture. Since Scripture is also the one place where we are given the way of salvation, entrance into the kingdom of God, and an infallible account of Christ, the Bible is the touchstone to which all truth claims should be brought and by which all other truth must finally be measured.

An obvious corollary of what I am saying is that truth means nothing apart from God. Truth cannot be adequately explained, recognized, understood, or defined without God as the source. Since He alone is eternal and self-existent and He alone is the Creator of all else, He is the fountain of all truth.

If you don’t believe that, try defining truth without reference to God, and see how quickly all such definitions fail. The moment you begin to ponder the essence of truth, you are brought face to face with the requirement of a universal absolute—the eternal reality of God. Conversely, the whole concept of truth instantly becomes nonsense (and every imagination of the human heart therefore turns to sheer foolishness) as soon as people attempt to remove the thought of God from their minds.

That, of course, is precisely how the apostle Paul traced the relentless decline of human ideas in Romans 1:21-22: “Although they knew God, they did not glorify Him as God, nor were thankful, but became futile in their thoughts, and their foolish hearts were darkened. Professing to be wise, they became fools.”

There are serious moral implications too, whenever someone tries to dissociate truth from the knowledge of God. Paul went on to write, “Even as they did not like to retain God in their knowledge, God gave them over to a debased mind, to do those things which are not fitting” (Romans 1:28). Abandon a biblical definition of truth, and unrighteousness is the inescapable result. We see it happening before our eyes in every corner of contemporary society. In fact, the widespread acceptance of homosexuality, rebellion, and all forms of iniquity that we see in our society today is a verbatim fulfillment of what Romans 1 says always happens when a society denies and suppresses the essential connection between God and truth.

If you reflect on the subject with any degree of sobriety, you will soon see that even the most fundamental moral distinctions—good and evil, right and wrong, beauty and ugliness, or honor and dishonor—cannot possibly have any true or constant meaning apart from God. That is because truth and knowledge themselves simply have no coherent significance apart from a fixed source, namely, God. How could they? God embodies the very definition of truth. Every truth claim apart from Him is preposterous.

Elaborate epistemologies have been proposed and methodically debunked one after another—like a long chain in which every previous link is broken. After thousands of years, the very best of human philosophers (Socrates, Plato, Aristotle, Descartes, Locke, Kant, Hegel, Kierkegaard, Nietzsche, Marx, James, and others) have all utterly failed to account for truth and the origin of human knowledge apart from God.

In fact, the one most valuable lesson humanity ought to have learned from philosophy is that it is impossible to make sense of truth without acknowledging God as the necessary starting point.

Truth is not subjective, it is not a consensual cultural construct, and it is not an invalid, outdated, irrelevant concept. Truth is the self-expression of God. Truth is thus theological; it is the reality God has created and defined, and over which He rules. Truth is therefore a moral issue for every human being.

How each person responds to the truth God has revealed is an issue of eternal significance. To reject and rebel against the truth of God results in darkness, folly, sin, judgment, and the never-ending wrath of God. To accept and submit to the truth of God is to see clearly, to know with certainty, and to find life everlasting.

(Adapted from The Truth War, © 2008, by John MacArthur. All rights reserved.)