The Tangible Reality of Knowing God Text: 1 John 2:3-6
Introduction: The War on Assurance
We live in an age that is desperately confused about what it means to know God. On the one hand, you have a sentimental, flabby evangelicalism that defines "knowing God" as having had a warm feeling during a worship song once, or repeating a prayer after a well-meaning youth pastor. This is a faith with no traction, no grip, no substance. It is a claim, a bumper sticker, a pious platitude, but it has no power to change a man's life. It produces people who say they know God but whose lives are functionally atheistic.
On the other hand, you have a fearful, introspective piety that is always picking at the scab of its own assurance. These are the folks who are terrified of "works righteousness," and so they live in a constant state of spiritual anxiety, never sure if they are truly saved. They have been taught, rightly, that salvation is by grace alone, but they have misunderstood this to mean that the grace of God has no observable effect. Their faith is a disembodied intellectual assent, a doctrinal checkbox ticked, but it has no feet.
Into this confusion, the apostle John speaks with the force of a blacksmith's hammer on an anvil. He is not interested in your feelings, your claims, or your doctrinal precision if they are detached from the gritty reality of a transformed life. For John, knowing God is not a subjective mood; it is an objective reality that has tangible, verifiable consequences. He is writing to give Christians assurance, but not the cheap assurance of a pat on the head. He gives us a series of diagnostic tests, not so we can navel-gaze in fear, but so we can look at the fruit in our lives and say, with confidence, "Yes, God has been at work here."
This passage is a direct assault on the ancient heresy of Gnosticism, which taught that "knowledge" (gnosis) was a secret, mystical insight that had nothing to do with your behavior in the material world. You could "know" God and live like the devil. John says this is nonsense. It is a lie. He draws a bright, sharp line in the sand. You cannot separate knowing God from obeying God. You cannot separate abiding in Christ from walking like Christ. To attempt to do so is to prove that you do not know Him at all.
The Text
And by this we know that we have come to know Him, if we keep His commandments.
The one who says, "I have come to know Him," and does not keep His commandments, is a liar, and the truth is not in him;
but whoever keeps His word, truly in him the love of God has been perfected. By this we know that we are in Him:
the one who says he abides in Him ought himself to walk in the same manner as He walked.
(1 John 2:3-6 LSB)
The Litmus Test of Knowledge (v. 3)
John begins with a clear, diagnostic statement. How can you be sure? How can you have settled confidence that your faith is the real article?
"And by this we know that we have come to know Him, if we keep His commandments." (1 John 2:3)
Notice the structure. The evidence is obedience. The conclusion is knowledge of God. John is not saying that we come to know God by keeping His commandments. That would be legalism, and it would be a damnable heresy. We are saved by grace through faith, period. But the faith that saves is never a faith that is alone. A living tree produces fruit. A living faith produces obedience. John is giving us the primary evidence, the chief sign, that a genuine transaction has occurred between our soul and God. The proof is in the pudding, and the pudding is a life of glad-hearted obedience.
The phrase "keep His commandments" is not about a grim, tight-lipped perfectionism. The word for "keep" here has the sense of guarding, watching over, or treasuring. It's not the begrudging obedience of a slave who fears the whip, but the joyful obedience of a son who loves his father and wants to please him. It is a disposition of the heart. Is the grain of your life, the overall trajectory, bent toward obeying God's Word? Do you treasure His law? When you sin, does it grieve you? Do you confess it and get back up, determined to walk in His ways? That is the mark of a true believer. It is not about the absence of sin, but about the direction of your heart's desire.
This is a frontal assault on what we call antinomianism, the idea that because we are under grace, the law of God has no bearing on our lives. This is a lie from the pit. Grace does not abolish the law; it fulfills it in us and enables us to obey it for the first time. The law shows us our sin and drives us to Christ, and then Christ sends the Spirit to write that same law on our hearts so that we might walk in it.
The Antithesis of Truth and Lies (v. 4)
John is a master of the antithesis. He leaves no gray area, no middle ground. You are either in the light or in the darkness. You are either of God or of the devil. Here, he applies that sharp distinction to the matter of profession versus practice.
"The one who says, 'I have come to know Him,' and does not keep His commandments, is a liar, and the truth is not in him;" (1 John 2:4)
This is not polite language. John does not say the man is "mistaken" or "sincerely wrong." He says he is a liar. Why? Because truth is not just a set of propositions you affirm; it is a reality that takes up residence in you and changes you from the inside out. If the truth is "in him," it will necessarily produce a life that corresponds to that truth. If a man claims to be a swimmer but refuses to get in the water, his claim is a lie. If a man claims to know the God of holiness but lives a life of unrepentant rebellion, his claim is a lie.
The truth is a person, Jesus Christ, who is "the way, the truth, and the life." To have the truth "in you" is to have Christ in you. And if Christ is in you, He will not be an idle houseguest. He will begin to clean house. He will rearrange the furniture. He will conform you to His own image. A profession of faith that is not accompanied by a transformed life is a counterfeit profession. It is a verbal claim that is being actively contradicted by the evidence of one's life. And in God's courtroom, actions speak louder than words.
The Perfection of Love (v. 5)
John now moves from the negative ("is a liar") to the positive, showing what the genuine article looks like.
"but whoever keeps His word, truly in him the love of God has been perfected. By this we know that we are in Him:" (1 John 2:5)
Here, "keeps His word" is parallel to "keep His commandments" in the previous verses. But notice the result. In the one who obeys, "the love of God has been perfected." This doesn't mean we become sinlessly perfect or that our love for God becomes flawless. The word "perfected" here means brought to its intended goal, matured, or completed. Think of a green apple. It is a true apple, but it is not yet a mature apple. God's love for us is the root, and our obedience is the process by which our responsive love for Him matures and comes to fruition.
How does this work? God's love is poured into our hearts by the Holy Spirit (Romans 5:5). That love is the engine of our obedience. Jesus said, "If you love me, you will keep my commandments" (John 14:15). So, love produces obedience. But John shows us that the cycle continues: that very obedience becomes the context in which our love is strengthened, tested, and brought to maturity. It is like a muscle. The more you exercise it through acts of obedience, the stronger your love for God becomes. And this, John says, is another way "we know that we are in Him." The evidence of a maturing, obedient love is a powerful ground for our assurance.
The Obligation to Imitate (v. 6)
Finally, John brings it all together in the most practical, Christ-centered way possible. What does this obedience look like in shoe leather?
"the one who says he abides in Him ought himself to walk in the same manner as He walked." (1 John 2:6)
To "abide in Him" is to live in intimate, dependent fellowship with Christ. It is the language of the vine and the branches from John 15. If you claim to be connected to the True Vine, there is an obligation, a moral necessity ("ought"), that flows from that claim. You ought to look like the Vine. The life of the Vine ought to be flowing through you, producing His character in you.
"To walk in the same manner as He walked" is the ultimate summary of the Christian life. Our standard is not a list of rules; it is a Person. We are to imitate Christ. His life of perfect, loving obedience to the Father is our pattern. How did He walk? He walked in humility, in dependence on the Father, in love for the brethren, in holiness, in speaking the truth, and in sacrificial service. He kept the commandments of His Father perfectly.
This is the goal of our sanctification. We are being conformed to the image of the Son. This is not a call to earn our salvation by imitating Jesus. It is a call to live out the salvation we have already been given. Because we are united to Him by faith, we now have the Spirit of Christ dwelling in us, enabling us to begin to walk as He walked. It is a high and holy calling, and one we will pursue for the rest of our lives. But the pursuit itself, however imperfect, is the evidence that we are His.
Conclusion: Faith That Works
John's logic is inescapable. True knowledge of God is not a secret password or a warm fuzzy. It is a life-altering reality that demonstrates its existence through obedience. A claim to know God without the fruit of obedience is a lie. A life of obedience, flowing from a heart of love, is the sign that God's love is maturing in us. And the ultimate shape of that obedience is a life that increasingly mirrors the walk of the Lord Jesus Christ Himself.
This is not meant to discourage the struggling saint. It is meant to demolish false assurance and to establish true assurance on solid ground. Do not look inward to the quality of your feelings. Do not look outward to the approval of men. Look to Christ, your perfect Advocate. And then look at the trajectory of your life. Do you love what He loves? Do you hate what He hates? Is the desire of your heart to walk as He walked? If the answer is yes, however many times you stumble and fall, then you have every reason to be assured. That desire is the work of His Spirit in you. It is the evidence of life. It is how we know that we know Him.