How to Know That You Know God

Recap: The Purpose of 1 John

If you remember from last week, we talked about one of the specific reasons why John is writing this epistle. It's not different from the first four verses, where John said he's writing these things so that your joy may be full, complete, and lacking nothing. The whole purpose of the book is that we would have joy in the message of Jesus Christ.

John explains a brief definition of that message: People who have fellowship with God don't have fellowship with sin. People who have fellowship with God don't continue to practice sin, and he's going to stress that idea again in coming passages. He writes these things to give us joy by understanding what a Christian is. You have joy by being a Christian.

As he talks about the ways to spot a Christian, you can examine your own life to see how much of a genuine Christian you actually are—by examining the way you live. There's a lot of talk that all you need is faith, with no reason to focus on what you do. Faith alone saves, but saving faith is never alone. Saving faith is always accompanied by a lifestyle that demonstrates faith, that shows what a true Christian is.

You're not saved because of what you do, but because you're saved, there is a change in what you do. That change is based on understanding that Jesus is light, God is light, and because you are in Christ, in the light, there is complete exposure of your life. Light exposes. Jesus exposes our life, as 1 John 1:9 says:

If we confess our sins, he is faithful and just to forgive us our sins.

It's often understood as confessing sins to God, but the passage doesn't specify that. A Christian walks in the light, with their life completely exposed by Jesus Christ. In that exposure, sins are made known, and they rest in those sins being forgiven.

This is important: It's not just putting sins out there to be embarrassed or ashamed. You expose your sins because you trust Jesus to save and forgive you. That's why 1 John 2:1 says John writes so that you don't sin, but if you do, you have an advocate with the Father, Jesus Christ the righteous, the propitiation for your sins.

Anybody who continues to sin after becoming a Christian continues to trust in the finished work of Jesus on the cross. A Christian does not continue to hide their sin. A Christian has their life completely exposed because they trust in Jesus Christ. Anyone who genuinely believes Jesus has forgiven their sins has no problem confessing.

The "Get Out of Jail Free Card" Illustration

Imagine you're caught by a police officer for breaking the law—drunk, speeding, throwing Molotov cocktails. If not pardoned, you'd deny it to avoid trouble. Or at home, if parents ask if you did something wrong, you'd lie or blame a sibling—unless you had a "get out of jail free card" redeemable for any offense.

Then, if parents ask, "Did you punch a hole in the wall with a baseball bat?" you'd say, "Yes, but here's my card." It's easy to confess when you know you're covered.

The tendency is to think this means you can sin freely—kick the neighbor's cat, throw rocks at their truck. But John writes explicitly against that. He's not telling you these things so you sin; he's telling you so you don't sin—not perfectly, but those sins are still covered.

Grasping that Jesus was crucified for your sins motivates you to stop sinning because he's the propitiation—Jesus took the wrath of God meant for you.

Imagine your parents crucify your innocent brother instead of punishing you for the hole in the wall. He goes willingly, in agony, nails through his flesh, blood spilling, dying. That's why you're free. It wouldn't feel good. You wouldn't celebrate with a party hat. It would sting, realizing every sin—sexual sin, lies, anger—was placed on him.

Jesus, sinless, became your brother through his work. God treated his Son as if he did everything wrong in your life, putting him to a horrific death. If you think that means you can sin freely, you haven't received knowledge of Jesus Christ, new birth, conversion by grace through faith.

John knows the effect of these truths: They make people not sin—those in the light.

By This We Know: Keeping His Commandments

And by this we know that we have come to know him, if we keep his commandments. Whoever says “I know him” but does not keep his commandments is a liar, and the truth is not in him, but whoever keeps his word, in him truly the love of God is perfected. By this we may know that we are in him: whoever says he abides in him ought to walk in the same way in which he walked.

Notice verse 3: By this we know that we have come to know him, if we keep his commandments. John continues his radical theme from chapter 1: You can tell if somebody is a Christian. You can tell if you're a Christian. As Peter said, make your calling and election sure.

If you claim to be a Christian, examine your life routinely. The world judges morality by feelings—if it feels good, it's good. John says don't listen to that. There's a black-and-white way to know: Do what God says.

Jesus said in John 15 that those who abide in him obey him. Test if you're his follower: Do you do what Jesus commands? When you think about your life, how often do you ask, "Am I doing what God says or what I want?" Probably what you want more often than not.

John says: If someone says "I know God" but does not keep his commandments, that person is lying—a liar with no truth in them. It's possible to know that you know God. It's not a hobby, a decision like picking a school or job. It's not going through motions of an assumed religion.

People are hostile to Christianity—probably a good reason to believe it's true, as John will say. But you can test: Does your life match what God says? Are you keeping his commandments?

What Does It Mean to Keep His Commandments?

The big question: What does it mean to keep his commandments? Verse 5: Whoever keeps his word, in him truly the love of God is perfected.

In context, it involves not hating your brother, living in repentance, lives publicly exposed because Jesus forgives. It's keeping the word, the message of God—love and the gospel. Jesus summarized every commandment: Love God and love your neighbor.

Beloved, I am writing you no new commandment, but an old commandment that you had from the beginning. The old commandment is the word that you have heard. At the same time, it is a new commandment that I am writing to you, which is true in him and in you, because the darkness is passing away and the true light is already shining.

It's an old commandment you heard, but new because true in him—Jesus Christ.

Recognizing if we're keeping commandments: Do you love God? Love the person next to you? Love those you fellowship with? Love people hostile to you? Other writers describe Christians by fruits of the Spirit: love, joy, peace, patience, kindness, gentleness, goodness, self-control.

Acts Christians gathered frequently, devoted to apostles' teaching. Keeping his word isn't just having a Bible—actively open it to understand loving God and others.

We're not talking claims: "I love God, I'm righteous." But people who say and do. The one who keeps God's word has the love of God perfected—removal of sin, increasing God, increasing love.

The Father, Son, Holy Spirit enjoy perfect, infinite love—euphoric joy. That love can be perfected in you, enabling endurance through suffering.

Walk as He Walked

Verse 6: Whoever says he abides in him ought to walk in the same way in which he walked. Our lives should look like Jesus'. We're called Christians—"little Christs." If we abide in him, our lives should resemble his.

How much do you pray like Jesus? Care for others like Jesus, even non-elect, pouring common grace? He knew some would reject him, yet healed and fed them.

Whoever says he is in the light and hates his brother is still in darkness. Whoever loves his brother abides in the light, and in him there is no cause for stumbling. Whoever hates his brother is in the darkness and walks in the darkness, and does not know where he is going, because the darkness has blinded his eyes.

Further on abiding, being in light, not hating. Examine how you act toward others—not just love God, but love each other. Walk as Jesus walked, care as he cared. Not just rest in salvation, but repent.

Verse 10: In him there is no cause for stumbling—not just not hating your brother, but no cause at all. Your attitude toward others influences sin. Obeying "love your neighbor" removes stumbling blocks.

These are descriptions of Christians: Keep God's commandments—in New Testament light of Jesus, loving God and neighbor, obeying Jesus' words in Scripture. That's how you know if you know God.