“How then can a man be just with God? Or how can he be clean who is born of woman?” (Job 25:4)

Questions like this have been plaguing human beings since the beginning of time. Those who believe in a righteous God naturally wonder, “Am I righteous as well? Does He approve of me? Will I escape judgment? Does He love me?” This desire for assurance has sent people on lifelong journeys, many of which fail to provide them with the clarity they lack. Some conclude that it simply isn’t possible to know if God approves of us.

While scripture tells us that, “There is no one who does good, not even one,” (Psalm 14:3b) it also promises hope of salvation through Jesus Christ.  Moreover, it teaches that it is possible to be assured of one’s salvation, and that those who are truly in Christ will persevere to the end. Sadly, not all Christians cling to these scriptural truths. Instead, they spend their lives chasing any number of things that they hope will grant them some measure of assurance: the sacraments, good deeds, church attendance, etc. It is not difficult to see how this changes the Christian life entirely. Those who put their trust in these things have only a false hope, and many who try find their confidence ultimately shaken.

The Apostle John wrote a letter to address this very problem. “These things I have written to you who believe in the name of the Son of God, so that you may know that you have eternal life,” he said. (1 John 5:13) Not a hope that you have eternal life. Not an attempt to gain eternal life. No, he said that we can know that we have it.

John identifies six different marks of a true Christian in his first epistle. Let’s take a look at each of them, in no particular order.

1. Those who are in Christ walk in light and not in darkness.

In both his Gospel and his epistles, John uses light and darkness as metaphors of spiritual truths. Early on in 1 John, he writes, “If we say that we have fellowship with Him and yet walk in the darkness, we lie and do not practice 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.” (1 John 1:6-7) How should we interpret this? What exactly is meant by “light” and “darkness”?

We can certainly think of light in a general sense as a reference to truth or goodness. However, in his Gospel, John makes a clear connection between the light and Christ Himself. “In Him was life, and the life was the Light of men,” he writes. “The Light shines in the darkness, and the darkness did not comprehend it.” (John 1:4-5) Elsewhere, we read, “Then Jesus again spoke to them, saying, ‘I am the Light of the world; he who follows Me will not walk in the darkness, but will have the Light of life.’” (John 8:12) Jesus also said, “I have come as Light into the world, so that everyone who believes in Me will not remain in darkness.” (John 12:46)

That is the first part of the metaphor: the light is Christ. Yet, John also uses the language of walking in light or darkness. What is meant by this? I believe it refers to a permanent mode of operating, or the way in which we choose to identify ourselves. Jesus also said in the Gospel of John, “Are there not twelve hours in the day? If anyone walks in the day, he does not stumble, because he sees the light of this world. But if anyone walks in the night, he stumbles, because the light is not in him.” (John 11:9-10) John made this connection elsewhere in his first epistle. “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 2:5b-6) Therefore, the pursuit of Christlikeness is central to this idea of walking. Not only does He light our way, but He is the object of our striving. “Abide in Me, and I in you,” Christ tells us. “As the branch cannot bear fruit of itself unless it abides in the vine, so neither can you unless you abide in Me.” (John 15:4)

Therefore, to walk in the light is to abide in Christ, to be conformed to His image, and to love Him rather than the darkness.

2. Those who are in Christ keep God’s commandments.

This is an absolutely central theme of 1 John: a true Christian will follow what God has commanded. That can seem very intimidating. After all, none of us keep those commands perfectly, but John makes an unbreakable connection between our status in Christ and obedience. “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, in him the love of God has truly been perfected.” (1 John 2:3-5a)

John could not be any clearer. If you don’t keep God’s commands, He says, you do not know Him. “By this we know that we love the children of God, when we love God and observe His commandments. For this is the love of God, that we keep His commandments; and His commandments are not burdensome.” (1 John 5:2-3) He even writes, “We know that no one who is born of God sins; but He who was born of God keeps him, and the evil one does not touch him.” (5:18) There is also this verse: “No one who is born of God practices sin, because His seed abides in him; and he cannot sin, because he is born of God.” (3:9)

Perhaps you are thinking, “But I still sin. Am I not in Christ?” This is where context is very important. Remember what I said about walking earlier: it is a way of operating. I do not believe John is saying that Christians will never succumb to the temptations of the sinful nature, for it still rages inside us all. (Romans 7:14-25) Rather, he is arguing that the children of God will be marked by a desire to obey God’s commands. They will progress in sanctification compared to where they were at the beginning. They will grow in obedience, and when they are made aware of sin, they will repent.

We must compare John’s words about obedience with something he says toward the beginning of this epistle. “If we say that we have no sin, we are deceiving 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 1:8-10) Here John makes two important points: 1) Christians do sin, and 2) those who confess their sins will be forgiven. In fact, he writes that if we claim we have no sin, we are liars.

Other verses also serve to illustrate that what John has in mind is a way of living. “Little children, make sure no one deceives you; the one who practices righteousness is righteous, just as He is righteous; the one who practices sin is of the devil; for the devil has sinned from the beginning.” (1 John 3:7-8) Therefore, our obedience to God’s commands represents the fact that we are aligning ourselves with the kingdom of God rather than the kingdom of the evil one. John tells us, “Do not love the world nor the things in the world. If anyone loves the world, the love of the Father is not in him.” (2:15) However, he also promises that “whatever is born of God overcomes the world; and this is the victory that has overcome the world—our faith.” (5:4)

3. Those who are in Christ love their brothers and sisters in Christ.

1 John is remarkable for its emphasis on the need to love our fellow Christians. John tells us, “If someone says, ‘I love God,’ and hates his brother, he is a liar; for the one who does not love his brother whom he has seen, cannot love God whom he has not seen.” (4:20) He connects this with his earlier language about light and darkness. “The one who says he is in the Light and yet hates his brother is in the darkness until now. The one who loves his brother abides in the Light and there is no cause for stumbling in him. But the one who 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.” (2:9-11)

If that language is not strong enough for you, consider this: “Everyone who hates his brother is a murderer; and you know that no murderer has eternal life abiding in him.” (3:15) This is in line with Jesus’ words in Matthew 5:21-22. Indeed, everything John says about loving the brethren is based upon the command he heard from Jesus at the Last Supper. “A new commandment I give to you, that you love one another, even as I have loved you, that you also love one another. By this all men will know that you are My disciples, if you have love for one another.” (John 13:34-35)

John does not stop with a general admonition to love our brothers and sisters in Christ rather than hating them. He also makes a practical application. “But whoever has the world’s goods, and sees his brother in need and closes his heart against him, how does the love of God abide in him? Little children, let us not love with word or with tongue, but in deed and truth.” (1 John 3:17-18) This matches very well with the book of James.

What use is it, my brethren, if someone says he has faith but he has no works? Can that faith save him? If a brother or sister is without clothing and in need of daily food, and one of you says to them, ‘Go in peace, be warmed and be filled,’ and yet you do not give them what is necessary for their body, what use is that? Even so faith, if it has no works, is dead, being by itself.

James 2:14-17

Even as saving faith results in sanctification, so it also results in love of the brethren and sensitivity to the needs of others.

4. Those who are in Christ believe in both the Father and the Son, acknowledging the Son’s testimony.

The Gospel of John is a testament to the full divinity of Christ and His complete equality with the Father. John likewise stresses in his first epistle that anyone who accepts the Father must also accept the Son. “Who is the liar but the one who denies that Jesus is the Christ? This is the antichrist, the one who denies the Father and the Son. Whoever denies the Son does not have the Father; the one who confesses the Son has the Father also.” (1 John 2:22-23)

Acknowledgment of Jesus’ identity as the Christ and the Son of God is a key marker of a true Christian, according to John. When he talks about testing the spirits, he says, “By this you know the Spirit of God: every spirit that confesses that Jesus Christ has come in the flesh is from God; and every spirit that does not confess Jesus is not from God; this is the spirit of the antichrist, of which you have heard that it is coming, and now it is already in the world. (1 John 4:2-3) He furthermore states, “Whoever confesses that Jesus is the Son of God, God abides in him, and he in God.” (1 John 4:15) John tells us that we must believe the testimony of the Son, for this is how the Father has chosen to grant us eternal life: through the work of the Son.

The one who believes in the Son of God has the testimony in himself; the one who does not believe God has made Him a liar, because he has not believed in the testimony that God has given concerning His Son. And the testimony is this, that God has given us eternal life, and this life is in His Son. He who has the Son has the life; he who does not have the Son of God does not have the life.

1 John 5:10-12

Consider these words of Christ, as quoted in the Gospel of John:

• “For not even the Father judges anyone, but He has given all judgment to the Son, so that all will honor the Son even as they honor the Father. He who does not honor the Son does not honor the Father who sent Him.” (John 5:22-23)
• “This is the will of Him who sent Me, that of all that He has given Me I lose nothing, but raise it up on the last day. For this is the will of My Father, that everyone who beholds the Son and believes in Him will have eternal life, and I Myself will raise him up on the last day.” (John 6:39-40)
• “I and the Father are one.” (John 10:30)
• “If anyone loves Me, he will keep My word; and My Father will love him, and We will come to him and make Our abode with him. He who does not love Me does not keep My words; and the word which you hear is not Mine, but the Father’s who sent Me.” (John 14:23-24)
• “He who hates Me hates My Father also.” (John 15:23)

It makes sense that John should write as he does when he heard Jesus say these things. The one who denies the words of the Son denies the words of the Father, and the one who denies the authority of the Son denies the authority of the Father. The one who accepts the Son accepts the Father, and the one who abides in the Son has communion with the Triune God. This is why the religious leaders of His day wanted to kill Jesus, for He “was calling God His own Father, making Himself equal with God”. (John 5:18b)

5. Those who are in Christ have the Holy Spirit.

In one section of his first epistle, John speaks of people who seem to be believers for a time, but turn out to be false. “They went out from us, but they were not really of us; for if they had been of us, they would have remained with us; but they went out, so that it would be shown that they all are not of us. But you have an anointing from the Holy One, and you all know.” (1 John 2:19-20) Notice the distinction John makes between those who “went out”—that is, left the church—and those who have “an anointing”. I believe the anointing John is talking about is the Holy Spirit.

The concept of anointing is closely linked with the Spirit in both the Old and New Testaments. (e.g. 1 Samuel 16:13, Isaiah 61:1, Acts 10:38) Those who are in Christ have this anointing as well. John writes, “By this we know that we abide in Him and He in us, because He has given us of His Spirit.” (1 John 4:13)

John’s Gospel probably has more to say about the Holy Spirit than the other three combined. Jesus told Nicodemus, “Truly, truly, I say to you, unless one is born of water and the Spirit he cannot enter into the kingdom of God. That which is born of the flesh is flesh, and that which is born of the Spirit is spirit.” (John 3:5-6) He also taught, “It is the Spirit who gives life; the flesh profits nothing; the words that I have spoken to you are spirit and are life.” (John 6:63) At the Last Supper, Jesus told the disciples, “But when He, the Spirit of truth, comes, He will guide you into all the truth; for He will not speak on His own initiative, but whatever He hears, He will speak; and He will disclose to you what is to come,” (John 16:13) making a strong connection between Himself and the Spirit. To be in Christ is to have the Spirit.

The Apostle Paul referred to the Holy Spirit as a “pledge” on three different occasions. (2 Corinthians 1:22 and 5:5, Ephesians 1:14) He writes, “In Him, you also, after listening to the message of truth, the gospel of your salvation—having also believed, you were sealed in Him with the Holy Spirit of promise, who is given as a pledge of our inheritance, with a view to the redemption of God’s own possession, to the praise of His glory.” (Ephesians 1:13-14) Ah, but how do we know if we have the Spirit? Another passage in Paul’s writings gives us some clues and makes a further connection to our inheritance in Christ.

For those who are according to the flesh set their minds on the things of the flesh, but those who are according to the Spirit, the things of the Spirit. For the mind set on the flesh is death, but the mind set on the Spirit is life and peace, because the mind set on the flesh is hostile toward God; for it does not subject itself to the law of God, for it is not even able to do so, and those who are in the flesh cannot please God. However, you are not in the flesh but in the Spirit, if indeed the Spirit of God dwells in you. But if anyone does not have the Spirit of Christ, he does not belong to Him. If Christ is in you, though the body is dead because of sin, yet the spirit is alive because of righteousness. But if the Spirit of Him who raised Jesus from the dead dwells in you, He who raised Christ Jesus from the dead will also give life to your mortal bodies through His Spirit who dwells in you. So then, brethren, we are under obligation, not to the flesh, to live according to the flesh—for if you are living according to the flesh, you must die; but if by the Spirit you are putting to death the deeds of the body, you will live. For all who are being led by the Spirit of God, these are sons of God. For you have not received a spirit of slavery leading to fear again, but you have received a spirit of adoption as sons by which we cry out, ‘Abba! Father!’ The Spirit Himself testifies with our spirit that we are children of God, and if children, heirs also, heirs of God and fellow heirs with Christ, if indeed we suffer with Him so that we may also be glorified with Him.

Romans 8:5-17

Note how this links back with some of John’s other themes: obedience to God’s commands, love of God rather than the world, identification with the Son of God, etc.

6. Those who are in Christ accept the gospel message as proclaimed by the apostles.

One final aspect of our assurance may not appear quite as often in 1 John, but I believe it is nevertheless important. At one point, John says, “We are from God; he who knows God listens to us; he who is not from God does not listen to us. By this we know the spirit of truth and the spirit of error.” (1 John 4:6) Who exactly is the “we” in these verses? Is John referring to himself in the third person? Does he mean himself and the readers? Does he mean all Christians? Elsewhere, John writes, “As for you, let that abide in you which you heard from the beginning. If what you heard from the beginning abides in you, you also will abide in the Son and in the Father.” (1 John 2:24) What did they hear from the beginning?

I believe what John is referring to is the gospel message as proclaimed by the apostles. Of course, he was an apostle, and his teachings were fully in line with the others. The Apostle Paul had the most to say about apostleship, and he also taught that there was a central gospel message handed down by the apostles from Christ. Note what he says to the Galatians.

I am amazed that you are so quickly deserting Him who called you by the grace of Christ, for a different gospel; which is really not another; only there are some who are disturbing you and want to distort the gospel of Christ. But even if we, or an angel from heaven, should preach to you a gospel contrary to what we have preached to you, he is to be accursed! As we have said before, so I say again now, if any man is preaching to you a gospel contrary to what you received, he is to be accursed!

Galatians 1:6-9

You might be thinking, “Paul says that if his own teaching disagrees with the gospel, they should obey the gospel instead.” This is true, and we know when Paul saw the Apostle Peter acting in a way that was contrary to the gospel, he rebuked him. (Galatians 2:11-21) However, Paul never suggests that he is teaching anything other than the gospel of Christ. Note his reference to “what you received”. (Galatians 1:9) He refers on six other occasions to “my gospel” or “our gospel”. (Romans 2:16 and 16:25, 2 Corinthians 4:3, 1 Thessalonians 1:5, 2 Thessalonians 2:14, 2 Timothy 2:8) This is not because Paul believed the gospel belonged to him or the apostles personally, or because he thought that he came up with it. No, he was simply identifying his teachings with those of Jesus Christ. They were the true gospel, and what was being taught by others in a contrary manner was a false gospel.

Note how Paul introduced himself to the Galatians in his letter: “Paul, an apostle (not sent from men nor through the agency of man, but through Jesus Christ and God the Father, who raised Him from the dead)…” (Galatians 1:1) He based his authority on the fact that he received his commission from God. Even as Jesus appointed the original apostles during his earthly ministry (Luke 6:13), Paul received a special commission directly from Christ (Acts 9:1-19, 1 Corinthians 9:1). This is why the apostles had a unique authority to proclaim the true gospel. We never read in scripture that they appointed other apostles after themselves, and indeed they could not have, because all the apostles were appointed directly by Christ. (The choice of Matthias as a replacement for Judas was revealed to the other apostles by God in Acts 1:21-26.)

We are told of the early Christians, “They were continually devoting themselves to the apostles’ teaching and to fellowship, to the breaking of bread and to prayer.” (Acts 2:42) When there was a controversy surrounding circumcision, “The apostles and the elders came together to look into this matter.” (Acts 15:6) They then sent out directions to all the churches. (Acts 15:22-30) No other ministers in Christian history have had this level of authority.

This is why it is necessary for us to accept the gospel as taught by the apostles. The principle of apostolic authority had a major impact on the creation of the New Testament canon. Only those books that were written by an apostle or a close associate of an apostle were accepted. (The Book of Hebrews was believed to fall into one of those two categories.) Likewise, only books that were in line with what the apostles taught were included.

The apostles existed for a short period of time to lay a firm foundation for Christian teaching, having experienced Christ firsthand and received a special commission directly from Him. As the Apostle Peter wrote, “For we did not follow cleverly devised tales when we made known to you the power and coming of our Lord Jesus Christ, but we were eyewitnesses of His majesty.” (2 Peter 1:16) That is why it is critical for us to accept not just any version of the gospel, but the one that was taught by the apostles, for they were inspired by the Holy Spirit. I believe this is what John meant when he said, “We are from God; he who knows God listens to us; he who is not from God does not listen to us.” (1 John 4:6a)

There you have it: six different marks of a true Christian. The person who has these things, according to John, may have assurance of eternal life. There are other passages in the New Testament that provide further assistance on this topic, but it is in 1 John that we receive the clearest summary of what it means to be in Christ.

All scripture quotations are from the New American Standard Bible, copyright The Lockman Foundation.