What Does John Mean by Sin?
Knowing God and the Reality of Sin:
Sin Paid For, Yet Still Present
One of the most important tensions a Christian must learn to understand is this: if Christ has completely paid for our sin, why do we still struggle with sin? This question has come up several times, and it is crucial because misunderstanding it can either produce false assurance or a guilty conscience that never rests. Scripture does not teach that Christ's atonement was incomplete, nor does it teach that salvation instantly eliminates every sinful tendency inherited through Adam. Christ's sacrifice completely addresses the guilt and penalty of sin, while the believer continues to experience the presence and effects of sin in this present life. First John is especially valuable because John refuses to separate these truths. He tells believers not to sin, acknowledges that believers still sin, provides for confession when they do sin, and immediately points them to Christ as their Advocate and atoning sacrifice. Understanding this tension allows the believer to take sin seriously without living under condemnation, and to have a clear conscience without pretending that sin is no longer present. The question is therefore not whether sin remains, but what sin means for someone who is already in Christ and whose sins have been fully paid for by Christ.Take a fresh look at 1 John 2:1-4 and discover again the completeness of God's grace for you in Jesus Christ, His only begotten Son.
“My little children, I am writing you these things so that you may not sin. But if anyone does sin, we have an advocate with the Father—Jesus Christ the Righteous One. He Himself is the atoning sacrifice for our sins, and not only for ours, but also for those of the whole world. This is how we know that we know Him: if we keep His commands. The one who says, ‘I have come to know Him,’ without keeping His commands is a liar. The truth is not in him.” — 1 John 2:1–4 (CSB)
John's treatment of sin in this passage is important because he connects sin, obedience, and knowing God. In 1 John 2:4, John describes sin without using the noun hamartia itself. Instead, he describes the behavior that reveals sin:
“The one who says, ‘I have come to know Him,’ without keeping His commands is a liar.”
The issue is not merely that someone has committed an isolated sinful act. John is addressing the contradiction between claiming to know God and persistently refusing to obey Him. In other words, John uses disobedience to God's commands as evidence of a person's spiritual condition. A person says: “I know Him.” But his life says: “I will not keep His commands.” John says those two claims cannot ultimately coexist.
This becomes clearer when the broader context of 1 John is considered.
Sin as Lawlessness
John later gives an explicit definition:“Everyone who commits sin also practices lawlessness; and sin is lawlessness.” — 1 John 3:4 (CSB)
Sin is therefore not merely making a mistake. Sin is lawlessness, a violation of God's revealed will.
Sin as Walking in Darkness
John also describes sin in terms of one's relationship with God:
“If we say, ‘We have fellowship with Him,’ and yet we walk in darkness, we are lying and are not practicing the truth.” — 1 John 1:6 (CSB)
Sin is incompatible with claiming to walk in fellowship with God while deliberately continuing in darkness.
Sin as Unrighteousness
John also says:
“All unrighteousness is sin, and there is sin that leads to death.” — 1 John 5:17 (CSB)
Sin is therefore also unrighteousness, the opposite of the righteousness God produces in His people.
So when John says in 2:4 that someone does not keep God's commands, he is describing sin in terms of lawlessness, darkness, and unrighteousness.
Sin Is Something the Believer Should Not Do
John begins chapter 2 with a very clear purpose:
“My little children, I am writing you these things so that you may not sin.”
That is the first important truth.
Sin is something the Christian is called to avoid.
John does not present grace as permission to continue in sin. His purpose in writing is that believers not sin.
But John immediately gives the second truth:
“But if anyone does sin, we have an advocate with the Father—Jesus Christ the Righteous One.”
Sin Is Also a Reality
John does not pretend that Christians have already reached sinless perfection.
He had already said:
“If we say, ‘We have no sin,’ we are deceiving ourselves, and the truth is not in us.” — 1 John 1:8 (CSB)
And:
“If we say, ‘We have not sinned,’ we make Him a liar, and His word is not in us.” — 1 John 1:10 (CSB)
John therefore holds two truths together:
We should not sin. But, we will still sin.
That is why believers need an Advocate.
And John has already given the means of restoration:
“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 (CSB)
Christ Is the Answer to Sin
John does not minimize sin. He shows us how serious it is by showing us what was necessary to deal with it.
“He Himself is the atoning sacrifice for our sins, and not only for ours, but also for those of the whole world.”
Christ is our Advocate and our atoning sacrifice.
Sin requires something greater than human effort.
It cannot be overcome by denying it.
It cannot be removed by redefining it.
It cannot be compensated for through religious performance.
It requires Christ.
The seriousness of sin and the sufficiency of Christ therefore stand together.
Does 1 John 2:4 Require Perfect Obedience?
This is where 1 John 2:4 must be read carefully.
“The one who says, ‘I have come to know Him,’ without keeping His commands is a liar. The truth is not in him.”
John is not saying that a Christian must never commit a sin.
That interpretation would contradict what he has just written. John has already acknowledged that believers sin. He has already provided for confession and forgiveness. He has already identified Christ as the believer's Advocate.
So what is John confronting?
A persistent pattern of disobedience that contradicts a person's profession of knowing God.
The distinction is between stumbling into sin and walking in a pattern of disregard for God's commands.
The Pattern Matters
The wording “without keeping His commands” uses the Greek present tense, which can describe an ongoing or characteristic pattern of behavior.
John's concern is therefore not the believer who falls, recognizes the sin, confesses it, and turns back toward God.
His concern is the person who claims to know God while habitually disregarding God's commands.
That person has a contradiction between profession and practice.
This is why John's statement is so strong:
“The truth is not in him.”
John is not measuring whether someone has achieved moral perfection.
He is examining whether the person's life is consistent with his claim to know God.
Knowing God Produces Obedience
John's argument is therefore straightforward:
Knowing God produces obedience to God.
Not flawless obedience.
Not sinless perfection.
But genuine, ongoing obedience.
A person who truly knows Christ will not be indifferent toward His commands.
When he sins, he confesses it. When he falls, he turns back. When God's Word exposes something wrong, he does not simply reject God's authority. His life increasingly moves toward obedience. That is the evidence John is looking for. The issue is not: “Have I ever sinned?” John has already answered that. Yes.
The issue is:
“What does the pattern of my life reveal about whether I truly know Him?”
A stumble is not the same thing as a settled direction.
A failure is not the same thing as persistent rebellion.
Confession is not the same thing as denial.
And struggling against sin is not the same thing as making peace with sin.
John is calling believers to examine the relationship between their profession and their practice.
We say, “I know Him.”
John asks whether our lives increasingly demonstrate that we do.
And when we fail, we do not run from Christ.
We have an Advocate with the Father, Jesus Christ the Righteous One.
THE LAST POINT
Life can hurt us so deeply that, at times, we simply do not respond as we should. That is not an excuse for sin – there are no excuses for sin – but it is a recognition of human weakness. Sometimes we are knocked down so hard that we retreat into ourselves and cannot see the way out. Perhaps that is one reason Scripture is so full of instructions about “one anothering” (a topic coming soon) – bearing one another’s burdens, encouraging one another, forgiving one another, comforting one another, restoring one another, and loving one another. In our darkest hours, the church needs the Church. We need brothers and sisters who understand that struggling believers do not need condemnation piled upon their wounds; they need the grace and truth of Christ lived out toward them. This is the Church – people themselves saved by the grace of God through faith in the finished work of the Son of God, helping one another stand again in that same grace.
Remember this in your deepest rebellion, pain and wondering:
We have an Advocate with the Father, Jesus Christ the Righteous One.
ReflecT
Does the pattern of my life demonstrate an increasing desire to obey Christ, even though I still stumble and sin?
When God's Word exposes sin in my life, do I confess it and turn toward Christ, or do I excuse, redefine, or deny it?
Prayer
Father, help me to know You truly and to let that knowledge transform the way I live. Keep me from self-deception and from treating sin casually. When I stumble, lead me to confession and repentance, trusting in Jesus Christ, my Advocate and atoning sacrifice. Let my life increasingly demonstrate that I truly know Him. Amen.