1 John, Part 3: How to Be Sure You Know Jesus

1 John 2:3-11 (BSB)

We are in week three of our sermon series on 1 John. John has been giving careful instructions on how we must walk in the light in order to have fellowship with God and with other believers. As he said in 1 John 1:3, “We proclaim to you what we have seen and heard, so that you also may have fellowship with us.”

We concluded last week’s sermon with the first two verses of chapter 2 which say, “My little children, I am writing these things to you so that you will not sin. But if anyone does sin, we have an advocate before the Father—Jesus Christ, the Righteous One. He Himself is the atoning sacrifice for our sins, and not only for ours but also for the sins of the whole world.”

Because he’s writing to people who already believe, it seems like John is confident that his readers already know this part of the Gospel message. For rather than spending time explaining how someone comes to faith, he’s more concerned with what happens after someone believes. And now, he wants to bring assurance to the believers and explain to them how they can be sure they know Jesus.

But I wanted to repeat those first two verses, because without them, the next section could be confusing. So, keeping the above in mind, let’s read the next nine verses. 1 John 2:3-11 (BSB) says:

3 By this we can be sure that we have come to know Him: if we keep His commandments. 

4 If anyone says, “I know Him,” but does not keep His commandments, he is a liar, and the truth is not in him.

5 But if anyone keeps His word, the love of God has been truly perfected in him. By this we know that we are in Him:

6 Whoever claims to abide in Him must walk as Jesus walked.

7 Beloved, I am not writing to you a new commandment, but an old one, which you have had from the beginning. This commandment is the message you have heard. 

8 Then again, I am also writing to you a new commandment, which is true in Him and also in you. For the darkness is fading and the true light is already shining.

9 If anyone claims to be in the light but hates his brother, he is still in the darkness. 

10 Whoever loves his brother remains in the light, and there is no cause of stumbling in him. 

11 But whoever hates his brother is in the darkness and walks in the darkness. He does not know where he is going, because the darkness has blinded his eyes.

There is a lot to understand in these verses, so I would like to go back through it, taking it verse by verse. Verse 3 says, “By this we can be sure that we have come to know Him: if we keep His commandments.”

To properly understand this verse, we need to remember what John said about Jesus’ death on the cross being the atoning sacrifice for the sins of the whole world, because otherwise we might think that good works, like keeping the commandments, earn us our salvation. John doesn’t seem concerned that people will mistake him on this point, though.

What he does seem concerned about is the same thing we ought to be concerned about, too: that there are people (maybe even some to whom he’s writing) who say they believe in Jesus, but they are not following His commands. And the point John wants to make is: the way to be sure you know Jesus is to check and see if you’re following Jesus’ commands.

Knowing this simple test accomplishes two important things. First, it brings needed conviction to anyone who, on hearing this, might realize they need to confess their sins and repent. Second, it gives us a simple way to guard against others who claim to be Christians but are not. Because, as John adds in verse 4, “If anyone says, ‘I know Him,’ but does not keep His commandments, he is a liar and the truth is not in him.”

Did you notice that this time, John changed the pronouns? Instead of saying, ‘if we say we know Him, but we don’t keep His commandments, we are liars,’ he’s said, ‘if anyone says…he is a liar.’ Later in his letter, John is going to warn everyone about being led away by deceivers. Well, this is one way to determine if someone is a liar: is the person who is claiming to speak for God keeping Jesus’ commandments? If not, that person shouldn’t be trusted.

But even though John switched pronouns, we shouldn’t think this applies only to deceivers. He’s still pointing out that how we can be sure that we have come to know Jesus is if we keep His commandments. I think we should personalize that warning because really, this is a restatement of what John said in 1 John 1:6, which says, “If we say we have fellowship with Him yet walk in the darkness, we lie and do not practice the truth.”

So, if we say we know Jesus, but we don’t keep His commandments, then we are lying and walking in darkness, because in order to be in the light, we have to walk in the light.

Some people might think this sounds harsh, but I don’t think John sees it that way. He’s just repeating things that he personally heard Jesus say. And if we want to be sure that we know Jesus, we will keep Jesus’ commandments, too.

Did you notice, though, that John never explains what commandments he’s talking about? I think that is because, again, he assumes the people he’s writing to already know what he’s talking about. But so that we are clear about what John is referring to, too, let’s read what Scripture says.

In John 15:9-12, Jesus says: “As the Father has loved Me, so have I loved you. Remain in My love. If you keep My commandments, you will remain in My love, just as I have kept My Father’s commandments and remain in His love. I have told you these things so that My joy may be in you and your joy may be complete. This is My commandment, that you love one another as I have loved you.”

That sounds very similar to all that John’s been writing in this epistle, doesn’t it? Jesus Himself says that if we keep His commandments, we will remain in His love. Jesus had said this earlier, too, in John 14:15, when He said, “If you love Me, you will keep My commandments.”

So, looking at the next verses, 1 John 2:5-6 says, “But if anyone keeps His word, the love of God has been truly perfected in him. By this we know that we are in Him: Whoever claims to abide in Him must walk as Jesus walked.”

In last week’s sermon, I quoted Alexander MacLaren, and I want to repeat part of what he said because I don’t think I can say it as succinctly as he did. He said: “Only remember John’s ‘if.’ The ‘blood of Jesus will progressively cleanse us until it has cleansed us from all sin,’ on condition that we ‘walk in the light,’ not otherwise. If the main direction of our lives is towards the light; if we seek, by aspiration and by effort, and by deliberate choice, to live in holiness, then, and not else, will the power of the life of Jesus Christ deliver us from the power of sin and death.”

Just as we must walk in the light to be sanctified, we must keep His Word for the love of God to be perfected in us. There is action required on our part. John wants them to really understand this point: the love of God will be progressively perfected in us as we walk as Jesus walked, following His command to love one another as He has loved us.

When John says that “Whoever claims to abide in Him must walk as Jesus walked,” he’s not stating new information. And in fact, that’s exactly what John says next. In verse 7, he says, “Beloved, I am not writing to you a new commandment, but an old one, which you have had from the beginning. This commandment is the message you have heard.”

We’ve all heard this message, too, haven’t we? Or has it been lost? Do we hear very often that, to abide in Him, we must walk as Jesus walked?

First, what does it mean to “abide in Him”? The Greek word for “abide” is meno, and it means to remain, to stay, to continue, to dwell. It’s the same word that Jesus uses in John 15:10 when He said, “If you keep My commandments, you will remain in My love, just as I have kept My Father’s commandments and remain in His love.” And so, John is repeating: if we keep God’s Word, then the love of God not only remains or abides in us, but is perfected in us.

But we have to know God’s Word in order to keep it. If we don’t know what God’s Word says, how can we follow and obey it? So, to be sure that we are following His commands, we had better be reading God’s Word on a daily basis, don’t you agree?

As we read His Word, we will discover exactly what Jesus wants us to do. As Jesus said in John 13:14, “I have set you an example so that you should do as I have done for you.”

Jesus spoke those words after He had washed the disciples’ feet. But as Ellicott explains in his commentary, “The example is in the principle, not in the specific act; it is not ‘that which I have done to you,’ but ‘according as I have done to you.’ The imitation is to be worked out in applying the same principle of love and self-sacrifice in all the varying circumstances of life in which we are placed.”

That means that we don’t need to literally wash other Christians’ feet, but we should humble ourselves and do the equivalent. That means we are to serve others and take care of other people’s needs. This is the old message that Jesus consistently preached and told us to emulate. As John said, it’s not a new idea.

But then, being an effective teacher, John adds to this and says in verse 8, “Then again, I am also writing to you a new commandment, which is true in Him and also in you. For the darkness is fading and the true light is already shining.”

Barnes’ Notes on the Bible says, “There can be no doubt here that John refers to the commandment to ‘love one another,’ and that it is here called new, not in the sense that John inculcated it as a novel doctrine, but in the sense that the Saviour called it such.”

That verse Barnes is referencing is John 13:34, in which Jesus says, “A new commandment I give you: Love one another. As I have loved you, so you also must love one another.” John is writing of that “new commandment.” That love that Jesus demonstrated to the whole world is the “true light” that is already shining. And when we love one another, we walk in the light, darkness fades, and true light shines.

So, what does “love one another” look like in practice? John is going to give a whole litany of things we can do to imitate Christ’s love, but the first thing we should consider is the greatest act of love that Jesus did for us: the Cross.

MacLaren writes about 1 John 2:7-8, saying: “The Cross of Christ is a commandment.” Then he explains that if we only view the Cross as the way of our salvation, we “foolishly limit its application and its power.” He says, “Jesus Christ Himself has told us that...’if any man serve Me, let him...follow Me.’ It is a law; it is ‘the law of liberty.’ So you have not done all that is needful when you have accepted the teaching of Christ in the Scriptures and the teaching of the Scriptures concerning Christ. Nor have you done all that is needful when, clasping Him and clinging simply to His Cross, you recognize in it the means and the pledge of your acceptance with God and the ground and anchor of all your hope. There is something more to be done. The Gospel is a commandment, and commandments require not only assent, not only trust, but practical obedience.”

MacLaren is rightfully pointing out that if we want to abide in Jesus, we must imitate the love that Jesus displayed by dying on the Cross for our sins. He loved us so much that He willingly endured the Cross. If we love Him, we will obey His command to love one another as He has loved us. He laid down His life for us. Jesus says in Luke 9:23, “If anyone wants to come after Me, he must deny himself and take up his cross daily and follow Me.” That sounds an awful lot like verse 6 of our text: “Whoever claims to abide in Him must walk as Jesus walked.”

This is the old and new message—if we want to abide in Jesus, we must walk as He walked.

John then gives us a simple metric to see if we are walking as Jesus walked. Verse 9 says, “If anyone claims to be in the light but hates his brother, he is still in the darkness.” John doesn’t mean our literal brother, though certainly it wouldn’t exclude him. John means our brother in Christ. But he also doesn’t intend to limit this to men. The Greek word used is adelphon and throughout the New Testament, it’s used to refer to brothers and sisters in Christ. Nowhere in the New Testament do we find a different word used specifically to refer to both brothers and sisters together. Just like the English use of “mankind,” the masculine single, or the plural adelphoi, is used when speaking about a group of people made up of both men and women.

Then, John expands on this and says in verse 10, “Whoever loves his brother remains in the light, and there is no cause of stumbling in him.”

This is an important point. Love means that we won’t do harm to others. We won’t cause them to fall into temptation. We won’t slander or lie to them. We won’t rejoice when they fall. We will seek to bless our fellow Christians and encourage them to walk in the light with us. In that way, we won’t be a stumbling block to them.

Finally, John warns again in verse 11, “But whoever hates his brother is in the darkness and walks in the darkness. He does not know where he is going, because the darkness has blinded his eyes.” If we hate our fellow Christians, then we are walking in darkness, and the darkness can blind us to the point where we don’t even know where we’re going.

This reminds me of what Jesus warned people about in John 12:35. He said, “For a little while longer, the Light will be among you. Walk while you have the Light, so that darkness will not overtake you. The one who walks in the darkness does not know where he is going.”

Those who walk in darkness don’t know where they are going. But if we walk in the Light, following Jesus’ example, then we can be sure to know, not only that we know Jesus, but where we are going. As we started our text for today, verse 3 said, “By this we can be sure that we have come to know Him: if we keep His commandments.” In the same way, by this we can be sure that we know where we are going: if we keep Jesus’ commandments.

If we follow the path of darkness, we will stumble and fall and could walk away from Jesus. But if we stay in the Light and follow His way of love, then we will continue to abide in Him.

Again, John is asking the believers he’s writing to—and he’s asking us: Am I walking as Jesus walked? What direction is my life moving in? Am I increasing in love, or am I growing more hateful?  

What direction are you going in? The way to know is simple. Ask yourself: Am I loving my fellow brothers and sisters in Christ?

If the answer is yes, then we can be sure that we know Jesus and are walking in the Light. But what if the answer is no or not really? Maybe you’ve realized that you’re not loving the way that Jesus does. If that’s you, let me encourage you. Remember how this chapter of 1 John started? The same Jesus who tells us that we must love as He does, is the same Jesus who is the advocate for us. If we confess that we are failing to love as He does, He will forgive us and help us. As we strive to follow His example, He will help us leave the darkness behind and walk in the Light.

Next week, we will explore this idea even more. In the meantime, let us leave the darkness completely. Let us step fully into the light and walk as Jesus walked—loving one another as He has loved us.

Pray: Heavenly Father, we thank You for demonstrating to us just how much You love us. Thank You for sending us Jesus to die on the Cross for our sins. Please help us turn away from any darkness and stay in the Light, loving one another as Jesus has loved us. Help us to walk in love each day, serving those around us. In the name of Jesus, we pray. Amen.