Do you really believe what you say and think you believe, and how can you know? The answer may at first brush appear obvious — “of course I believe what I say and think I do,” you might say. If you didn’t, after all, why would you be spending so much time engaged in the intellectual defense of it? This raises an interesting question: Can you believe that you believe something which you do not in fact believe in your heart? Is it possible that we deceive ourselves about what our own beliefs are?

So many people in our modern evangelical culture assent to a set of propositional truths about God but in their hearts are practical atheists. I believe that Scripture gives us examples of people of this category — people who were doctrinally sound but whose lifestyles did not bear out their professed beliefs. One such example is found in Isaiah 29:13-15:

And the Lord said: “Because this people draw near with their mouth and honor me with their lips, while their hearts are far from me, and their fear of me is a commandment taught by men, therefore, behold, I will again do wonderful things with this people, with wonder upon wonder; and the wisdom of their wise men shall perish, and the discernment of their discerning men shall be hidden.”Ah, you who hide deep from the Lord your counsel, whose deeds are in the dark, and who say, “Who sees us? Who knows us?”

These peoples’ problem was that, although they were assenting intellectually to propositional truths about God, in their heart of hearts they were practical atheists. This becomes clear in verse 5 when they are described as doing their wicked deeds in darkness and saying in effect in their hearts “No one is going to see us or know what we are doing.” From the outside, these men probably appeared to all as if they had their eyes nailed to heaven. But their hearts were full of impurity and lust and ungodliness. They lived after the adoration and admiration of men, but not that of God. If they truly believed what they professed to believe in their hearts, how would they have been able to say these things or delude themselves into thinking they could conceal their behavior from an omniscient God?

Another example is found in Malachi 1. In verses 6-8, we read,

A son honors his father, and a servant his master. If then I am a father, where is my honor? And if I am a master, where is my fear? says the Lord of hosts to you, O priests, who despise my name. But you say, ‘How have we despised your name?’ By offering polluted food upon my altar. But you say, ‘How have we polluted you?’ By saying that the Lord’s table may be despised. When you offer blind animals in sacrifice, is that not evil? And when you offer those that are lame or sick, is that not evil? Present that to your governor; will he accept you or show you favor? says the Lord of hosts.

When God speaks against the priests of Israel for despising and showing contempt for God’s name, the rejoinder from the priests is “How have we despised your name?” In other words, the priests protest, “We would never say that God’s not number 1. We’d never say he’s not on the throne as Lord over our lives. We’d never show contempt for God’s name.” In response, God says “You say it. Not with your mouth, not with your intellect, but with your life.” The behavior of the priests demonstrated that, although in their intellects and with their mouths they would have professed God to be Lord of their lives, their behavior told a very different story. They kept the best for themselves and gave God less than the best. It was apparent by their behavior that their respect for God was less than they had for their governor — for they would never have shown contempt for him in the way that they show contempt for God by the defective sacrifices that they bring to Him.

Hebrews 3:12 warns us to be cautious “lest there be in any of you an evil, unbelieving heart, leading you to fall away from the living God.” The writer to the Hebrews here warns us to be especially careful that, although we might assent to propositional truths about God with our intellect, even professing ourselves to be followers of Jesus, our heart can be unbelieving. Such a heart is described as being evil, and thus it has not been regenerated (indeed, when God saves us, he removes from us a heart of stone and gives us a heart of flesh — Ezekiel 36:26). This text, I believe, is therefore referring to individuals who believe themselves to be genuine believers, and yet, unknown to them, still have an unbelieving heart. Verse 19 of the same chapter speaks of unbelief as being the reason behind the inability of the rebellious Hebrews do enter into the promised land. I imagine that, were you to interview one of those rebellious Hebrews, their doctrine would be quite sound. They would be able to tell you about how God had parted the red sea and led them through the wilderness and provided for every one of their needs. Nonetheless, they were discontent, and, not trusting that God was working all things out for their good, had an unbelieving heart. They didn’t trust the faithfulness and promises of God, and this spoke volumes about what they actually believed in their hearts.

Scripture commands us over and over again to continuously examine our hearts to make sure that we are truly believers. 2 Corinthians 13:5 implores us to “Examine yourselves, to see whether you are in the faith. Test yourselves. Or do you not realize this about yourselves, that Jesus Christ is in you?—unless indeed you fail to meet the test!” In his epistle to the Ephesian church, the second-century church father (and disciple of John the Apostle) Ignatius of Antioch wrote the following:

Given a thorough-going faith and love for Jesus Christ, there is nothing in all this that will not be obvious to you; for life begins and ends with two qualities. Faith is the beginning, and love is the end; and the union of the two together is God. All that makes for a soul’s perfection follows in their train, for nobody who professes faith will commit sin, and nobody who possesses love can feel hatred. As the tree is known by its fruits, so they who claim to belong to Christ are known by their actions; for this work of ours does not consist in just making professions, but in a faith that is both practical and lasting. Indeed, it is better to keep quiet and be, than to make fluent professions and not be. No doubt it is a fine thing to instruct others, but only if the speaker practices what he preaches.

If I were to identify two themes that were predominant in the early years of the church, it would be unity and consistency. Back in the early years of the church, it was taken for granted that the mark of a true believer was the fruit manifested in his life.

Testing our hearts in the light of Scripture is so very important, for “the heart is deceitful above all things and desperately wicked,” (Jeremiah 17:9). It is so easy to delude ourselves into thinking we believe things which we in fact do not. In his classic book, Heaven Taken By Storm, the 17th century puritan Thomas Watson put it so well:

The heart is the greatest impostor; it will be ready to put one off with seeming grace, instead of saving. The heart will persuade that a slight tear is repentance; a lazy desire is faith. Now because the generality of people do not believe that there is such fallacy in their hearts, therefore they are so slow to examine them. This natural backwardness in us to self-reflection should cause us to offer the more violence to ourselves in making a thorough investigation and search of our hearts.

He goes on to talk about the importance of self-examination:

Without self-examination we can never know how it is with us. If we should die presently, we cannot tell to what coast we should sail; whether to hell or Heaven. It is reported of Socrates, when he was going out of the world, he had this speech, “I am now to die, and the gods know whether I shall be happy or miserable.” That man who is ignorant of the state of his soul needs have the trembling at the heart, as Cain had a shaking in his flesh. By a serious scrutiny of our hearts, we come to know to what prince we belong, whether to the prince of peace, or the prince of the air. If we will not try ourselves, God will try us. He will examine us, as the chief captain did Paul, by scourging, Acts xxii. 24. He will ask the same question as Christ, “whose is this image and superscription?” And if we cannot show him His own image, he will reject us.

One danger, especially for those involved in the intellectual defense of the faith (i.e. apologists), is that one’s Christianity becomes reduced to merely an intellectual belief, one that has little or no bearing on the way one lives. What sets real Christians apart from any other person of any religious affiliation is that we have a genuine relationship with the God of the Universe. That is something truly phenomenal which we should never take for granted.

What is there that separates us and sets us apart from, say, the Jehovah’s witnesses or the Mormons? Is it merely a difference in theological belief? If the only thing that makes you different from members belonging to those groups is a difference in doctrinal content, then you have to answer the question “In that case, do you believe that you are saved by your doctrine?” The Bible, however, makes it clear that we are not saved by our doctrine. As James 2:19 says, “You believe that God is one; you do well. Even the demons believe—and shudder!” If your doctrine is the only distinguishing factor, then you are in effect no different from a Jehovah’s witness or a Mormon and you have much reason to be afraid. You may have the correct doctrinal content and you may even be able to articulate and defend your beliefs with clarity and precision. But at the end of the day, before God, it will really do you no good. To quote Thomas Watson again, he writes in The Doctrine of Repentance,

Some bless themselves that they have a stock of knowledge, but what is knowledge good for without repentance? It is better to mortify one sin than to understand all mysteries. Impure speculatists do but resemble Satan transformed into an angel of light. Learning and a bad heart is like a fair face with a cancer in the breast. Knowledge without repentance will be but a torch to light men to hell.

Think about what beliefs you hold that are not reflected by the manner in which you live out your life! You believe that apart from the empowering grace of God you can do nothing in and of yourself. You are doctrinally correct, but the measure of your belief in this proposition is reflected by your prayer life — what does your prayer life say about whether you really believe this in your heart? You believe that God’s judgment for sin is an eternity separated from God in Hell — again, you are doctrinally correct, but the measure of your belief lies in your zeal for evangelism, intercessory prayer, and seeing soul’s saved. You believe that the Bible is God’s inspired revelation to mankind — but how often do you study and meditate upon it? You believe that God is sovereign, but are you content in all circumstances as Paul was (Philippians 4:11)?

The kingdom of Heaven is not easy to enter. Indeed, Jesus says in Matthew 11:12, “From the days of John the Baptist until now the kingdom of heaven has suffered violence, and the violent take it by force.” We also know that of those who profess Christ as Lord, few are said to enter through the narrow gate onto the narrow path that leads to life. It is far easier to enter through the broad gate onto the broad path that leads to destruction (see Matthew 7:13-23). Few find the former, but many enter through the broad gate.

Yearn for harmony between the mind and intellect. Strive as you might, you may never reach perfect harmony in this life, for we are all hypocrites in one way or another. But are you doing violence to yourself in mortifying sin? Are you wrestling with God in prayer? Are you putting idols to death? Are you seeking to grow more and more acquainted with Scripture? Among the scariest words in Scripture are found in Matthew 7:21-23:

“Not everyone who says to me, ‘Lord, Lord,’ will enter the kingdom of heaven, but the one who does the will of my Father who is in heaven. On that day many will say to me, ‘Lord, Lord, did we not prophesy in your name, and cast out demons in your name, and do many mighty works in your name?’ And then will I declare to them, ‘I never knew you; depart from me, you workers of lawlessness.’

Such individuals did not simply call Jesus “Lord”. They called him “Lord, Lord”. They were emphatic about their profession that Jesus was Lord, but they never had a relationship with Him. Indeed, they were never known by Him, and so they were rejected. Be sure that you are not one of those who will hear those painful, crushing, reverberating words: “I never knew you; depart from me, you workers of lawlessness.”