The Topography of Truth: Walking in the Light Text: 1 John 1:5-10
Introduction: The Great Evasion
We live in an age that has mastered the art of the evasion. Our entire culture is a conspiracy to avoid plain speech, objective realities, and sharp, clean distinctions. We prefer shadows, fog, and nuance, not because reality is nuanced, but because we want to hide in the nuance. We want to live in the gray areas because we are running from the stark, brilliant, and terrifying reality of the light. We have convinced ourselves that truth is a matter of personal perspective, that morality is a social construct, and that sin is an outdated category for therapeutic maladjustments.
But the Christian faith is not a participant in this great evasion. It is a declaration of war against it. The apostolic message, which John here summarizes, is not a suggestion or a contribution to the ongoing dialogue. It is a non-negotiable proclamation about the nature of ultimate reality. It is a message heard directly from Jesus Christ Himself, and it functions as the bedrock foundation for everything else. If you get this wrong, everything else unravels.
John begins his letter by establishing the historical, tangible reality of Jesus Christ, the Word of life. He is not talking about a philosophy; he is talking about a person whom he has heard, seen, and touched. And the central content of this person's message is this: God is Light. This is not a metaphor in the sentimental sense. It is a metaphysical statement. It is a declaration about the very being of God. And from this central declaration, a series of inescapable consequences flow. These consequences form a divine diagnostic test for anyone who claims to be a Christian. John is giving us a series of spiritual blood tests. You can say whatever you want about your spiritual health, but the tests do not lie. This passage is designed to demolish all hypocrisy, all self-deception, and all cheap grace by forcing us to answer a simple question: are we walking in the light, or are we stumbling in the dark?
This is intensely practical. There is no way to maintain the peace and purity of the church, no way to have genuine fellowship with God or with one another, apart from a rugged, honest, and continuous application of the truths in this passage. We must either walk in the light or admit we are liars.
The Text
And this is the message we have heard from Him and declare to you, that God is Light, and in Him there is no darkness at all. If we say that we have fellowship with Him and yet walk in the darkness, we lie and do not do the truth; but if we walk in the Light as He Himself is in the Light, we have fellowship with one another, and the blood of Jesus His Son cleanses us from all sin. If we say that we have no sin, we deceive ourselves and the truth is not in us. If we confess our sins, He is faithful and righteous to forgive us our sins and to cleanse us from all unrighteousness. If we say that we have not sinned, we make Him a liar and His word is not in us.
(1 John 1:5-10 LSB)
The Foundational Proclamation (v. 5)
John begins with the source and substance of the apostolic message.
"And this is the message we have heard from Him and declare to you, that God is Light, and in Him there is no darkness at all." (1 John 1:5)
First, notice the authority. This is not a message they invented. It is the message "we have heard from Him." This is received truth, not a creative insight. The apostles are couriers, not authors. Their job is to deliver the mail, not to edit it. This is why we must submit to the apostolic word; to reject it is to reject Christ Himself.
And what is the substance of this message? "God is Light." This is an absolute statement. Light, in Scripture, represents purity, holiness, truth, knowledge, and life. Darkness represents sin, falsehood, ignorance, and death. To say God is light is to say He is absolute, unadulterated holiness and truth. There is no admixture of evil in Him. There is no shadow of deceit. "In Him there is no darkness at all." This is not just a poetic flourish; it is a categorical exclusion. There is no shred of darkness in God's being. He is not 99% light. He is pure, unblinking, glorious light.
This demolishes all dualistic worldviews that see reality as an eternal struggle between good and evil, light and darkness. Darkness is not a co-eternal principle with God; it is a privation, a rebellion against the light. God is the uncreated reality; darkness is the shadow cast by a creature turning away from Him. This also sets the absolute standard. The standard for fellowship with God is not "trying hard" or "being sincere." The standard is the character of God Himself. And because He is pure light, fellowship with Him requires walking in that light.
The First Test: The Lie of Lawless Fellowship (v. 6)
From this foundational truth, John draws the first of three logical consequences, presenting it as a test.
"If we say that we have fellowship with Him and yet walk in the darkness, we lie and do not do the truth;" (1 John 1:6 LSB)
Here is the first test of a false profession. The claim is fellowship with God. "Fellowship" is the Greek word koinonia. It means sharing, partnership, communion. It means having something in common. The person in this verse claims to have koinonia with the God who is pure light. But his life, his "walk," is characterized by darkness. To "walk" in the darkness means to live a life defined by sin, to have a settled pattern of disobedience and moral rebellion. It is to live as though God's law does not matter.
John's verdict is blunt. He does not say the person is mistaken or confused. He says, "we lie." It is a bald-faced lie, because it is a flat contradiction. It is like saying, "I am in fellowship with fire," while living at the bottom of the ocean. It is an impossibility. You cannot be in communion with the God of light while your life is oriented around the darkness. Notice the result: we "do not do the truth." The truth is not just something to be believed; it is something to be done. A genuine faith is a walking faith. If your faith does not affect your feet, it is a dead faith.
The True Walk: Fellowship and Cleansing (v. 7)
In contrast to the lie, John presents the glorious reality of true Christian experience.
"but if we walk in the Light as He Himself is in the Light, we have fellowship with one another, and the blood of Jesus His Son cleanses us from all sin." (1 John 1:7 LSB)
To "walk in the Light" does not mean to achieve sinless perfection. If it did, the rest of the passage would be unnecessary. Rather, it means to live with our lives open and exposed to God. It means living honestly in the presence of the holy God who is light. It means we are not hiding. It means that when we sin, we bring it into the light, instead of trying to cover it up in the dark. Walking in the light means walking honestly. And that means you will always be dealing with your sins in a well-lit area. Christ is that light.
When we do this, two things happen. First, "we have fellowship with one another." True Christian koinonia is only possible in the light. When we are all hiding our sins in the dark, we are not having fellowship; we are just a collection of isolated hypocrites in the same room. But when we walk in the light, honestly dealing with our sin, we find that we have a profound, blood-bought unity with our brothers and sisters who are doing the same. Honesty breeds fellowship.
Second, "the blood of Jesus His Son cleanses us from all sin." This is a continuous action. The verb "cleanses" is in the present tense. As we walk in the light, bringing our sins into the open, the blood of Jesus is continually, moment by moment, washing us clean. This is not a one-time event at conversion, but an ongoing reality of the Christian life. The blood of Jesus is the divine solvent for all sin. The condition for this ongoing cleansing is not sinlessness, but rather the honest confession that walking in the light entails.
The Second Test: The Lie of Sinless Perfection (v. 8)
John now turns to a more subtle, but equally deadly, form of self-deception.
"If we say that we have no sin, we deceive ourselves and the truth is not in us." (1 John 1:8 LSB)
The first lie was claiming fellowship with God while living in sin. This lie is claiming to have no sin at all. This is the lie of the Gnostic, the perfectionist, the proud Pharisee. This person claims to have arrived at a state of sinlessness. John's diagnosis is that such a person is self-deceived. This is a curious thing, self-deception. It is where you tell yourself a lie, and you believe it. You are culpable for telling the lie, and you are culpable for believing such an obvious lie.
To say "we have no sin" is to be profoundly ignorant of two things: the holiness of God and the depravity of your own heart. The closer you get to the light, the more you see the dirt. The person who claims to have no sin is demonstrating that he is actually walking in deep darkness, blind to his own condition. The result is that "the truth is not in us." He has no grasp of reality.
The Divine Remedy: Confession and Forgiveness (v. 9)
Here we find the very heart of the gospel for the struggling saint. This is the way out of the darkness and the self-deception.
"If we confess our sins, He is faithful and righteous to forgive us our sins and to cleanse us from all unrighteousness." (1 John 1:9 LSB)
The alternative to denying our sin is confessing it. The Greek word for confess is homologeo. It is a compound word: homo means "same," and logeo is a verb form of logos, meaning "to speak" or "word." To confess, therefore, is to say the same thing about our sin that God says about it. It is to agree with God. If God calls it adultery, we don't call it an affair. If God calls it a lie, we don't call it a mild prevarication. Confession is honesty. We are sinful, and He is righteous. We do the confessing, and He does the cleansing.
And when we do this, look at God's response. "He is faithful and righteous to forgive us." Notice the words John uses. He does not say God is "merciful and kind," though He is. He says God is faithful and righteous, or just. Why? Because our forgiveness is not based on God setting aside His justice. It is based on His justice having been fully satisfied at the cross. God is faithful to His covenant promises, and He is just because Christ paid the penalty in full. For God not to forgive a confessed sin for which Christ died would be for Him to be unjust, to demand payment twice. Our forgiveness is therefore not a precarious hope, but a blood-bought certainty.
And the promise is gloriously comprehensive. He forgives "our sins", the ones we confess. But He also goes further, to "cleanse us from all unrighteousness." This covers the sins we are not even aware of, the deep roots of corruption that we cannot fully grasp. We confess what we know, and God, in His grace, cleanses us from all of it.
The Third Test: The Lie that Makes God a Liar (v. 10)
John concludes this section by restating the second test with even more severe implications.
"If we say that we have not sinned, we make Him a liar and His word is not in us." (1 John 1:10 LSB)
This is the climax of the argument. To deny our sin is not just self-deception (v. 8); it is a direct assault on the character of God. The entire Bible, God's Word, testifies to the universal sinfulness of man. The entire mission of Jesus Christ, His incarnation, death, and resurrection, is predicated on the fact that we are sinners in need of a Savior. "You shall call His name Jesus, for He will save His people from their sins" (Matthew 1:21).
Therefore, if you say, "I have not sinned," you are not just disagreeing with a doctrine. You are calling God a liar. You are saying that the cross was a tragic mistake. You are declaring the entire gospel to be fraudulent. This is the ultimate blasphemy. And the consequence is stark: "His word is not in us." If we reject the foundational premise of God's Word, our sinfulness, then none of His Word can find a home in us. We have locked the door against the only truth that can save us.
So the choice is plain. We can lie about our sin and remain in the dark, deceiving ourselves and maligning God. Or we can agree with God about our sin, walk in the light of His holiness, and find glorious, continuous fellowship and cleansing through the blood of His Son. This is the topography of truth. There is no middle ground, no shadowy valley to hide in. There is only the light and the dark. May God give us the grace to be honest men and women, and to walk in the light.