The following blog post was originally published in April, 2016. —ed.

What does biblical assurance look like? Can we spot the evidence of true faith and the Spirit’s sanctifying work in our lives? And how do we know what to look for?

The apostle John’s first epistle is devoted to answering those very questions. Surely no other passage of Scripture confronts the false promises of no-lordship theology with more force than this brief but potent letter.

John’s purpose statement is explicit: “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” (1 John 5:13, emphasis added). There the apostle spells out his intention. He is not trying to make believers doubt; he wants them to have full assurance. What he has to say will not shake genuine believers; though it should certainly alarm those with a false sense of assurance.

Inspired by the Spirit, John details seven factors that reveal whether a person is a genuine believer or a false convert. These are not tests an unbeliever must pass to become a believer, but points of examination for a professing believer to use in evaluating his own profession of faith.

True Believers Walk in the Light

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).

Walking in darkness is the antithesis of following Christ. All unsaved people walk in darkness; Christians have been delivered into the light: “You were formerly darkness, but now you are Light in the Lord; walk as children of Light” (Ephesians 5:8). To “walk in the light” means to live in the realm of truth. So all true believers are walking in the light—even when we sin. When we sin, “The blood of Jesus . . . cleanses us” (1 John 1:7). The verb tense there indicates that Christ’s blood continually cleanses us. When we sin, we are already being cleansed, so that no darkness ever clouds the light in which we dwell (cf. 1 Peter 2:9).

“Walk[ing] in the light” describes both positional and practical reality for the believer. To trust Jesus Christ is to walk in the light. To walk in the light is to heed the light and live accordingly.

True Believers Confess Their Sin

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)

The word for “confess” (homologeō) means “to say the same thing.” To “confess our sins” means to agree with God about them. This is a characteristic of all true Christians. They agree with God about their sin. That means they hate their sin; they don’t love it. They acknowledge that they are sinful, and yet they know they are forgiven and that they have an Advocate with the Father (1 John 2:1).

True assurance of salvation always goes hand in hand with an awareness of our own sinfulness. In fact, the more certain we are of salvation, the deeper our awareness of our sin becomes.

That may sound paradoxical, but it is the very thing that keeps Christians from falling into utter despair. We know we are sinners. We agree with God about that. We’re not surprised to discover sin in our lives, but nevertheless we hate it. We know we are forgiven and cleansed and that Christ is our Advocate. Far from using that knowledge to justify our sin, however, we see it as a motivation to mortify sin all the more: “I am writing these things to you that you may not sin” (2:1, emphasis added).

True Believers Keep His Commandments

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. . . . For this is the love of God, that we keep His commandments; and His commandments are not burdensome. (1 John 2:3-4; 5:3).

Here’s how we can be sure if we have come to know Him: We keep His commandments. This is a test of obedience, but it is not an obedience that is only the result of external pressure. It is the eager obedience of one who “keeps” the divine commandments as if they were something precious to guard.

Those who claim to know God yet despise His commandments are liars (1 John 2:4). “They profess to know God, but by their deeds they deny Him, being detestable and disobedient and worthless for any good deed” (Titus 1:16).

True Believers Love the Brethren

This test and the previous one are closely related:

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. (1 John 2:9–11; See also 3:10, 14-15; 5:2)

The reason these two tests are so closely related is that love perfectly fulfills the law. “He who loves his neighbor has fulfilled the law” (Romans 13:8). Here John echoes the words of Jesus that to love God and to love one’s neighbor fulfills the whole moral law (Matthew 22:37-40).

Love for fellow believers is a particularly important evidence of genuine faith. The point is not that love is intrinsic to us, or something that rises out of our own goodness. The love that is evidence of true faith is God’s love, which is being perfected in us: “If we love one another, God abides in us, and His love is perfected in us” (1 John 4:12). It is that dim reflection of divine glory in us that provides the subjective ground of our assurance.

True Believers Affirm Sound Doctrine

I have not written to you because you do not know the truth, but because you do know it, and because no lie is of the truth. 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. . . . By this we know the spirit of truth and the spirit of error. (1 John 2:21–23; 4:6)

John was writing in opposition to an early form of the gnostic heresy, which denied that Jesus Christ is fully God and fully man. He is saying that no one who truly is saved can fall into serious, Christ-denying error or heresy. Why? Because

you have an anointing from the Holy One . . . [and] the anointing which you received from Him abides in you, and you have no need for anyone to teach you; but as His anointing teaches you about all things, and is true and is not a lie, and just as it has taught you, you abide in Him. (1 John 2:20, 27)

Again, it is the divine work in us, not our own skill or achievements, that provide a sound basis for our assurance.

True Believers Follow After Holiness

If you know that He is righteous, you know that everyone also who practices righteousness is born of Him. . . . And everyone who has this hope fixed on Him purifies himself, just as He is pure. Everyone who practices sin also practices lawlessness; and sin is lawlessness. . . . No one who abides in Him sins; no one who sins has seen Him or knows Him. 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. . . . 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. (1 John 2:29; 3:3-4, 6–9)

Those verses have tripped many people up. The key to their meaning is the definition of sin in 1 John 3:4: “Sin is lawlessness.” The Greek word for “lawlessness” is anomia. It literally means, “without law,” and it describes those who live immoral, ungodly, unrighteous lives as a matter of continuous practice. They hate God’s righteousness and perpetually live as if they were sovereign over God’s law. This cannot be true of a genuine Christian.

The apostle is clearly not making sinless perfection a test of salvation. After all, he began his epistle by saying, “If we say that we have no sin, we are deceiving ourselves, and the truth is not in us” (1 John 1:8).

Nor is he making an issue about the frequency, duration, or magnitude of one’s sins. All Christians sin, and true believers are capable even of prolonged and heinous sin. The issue John is raising here has to do with our attitude toward sin and righteousness, our heart’s response when we do sin, and the overall direction of our walk.

Those who cling to the promise of eternal life but care nothing for Christ’s holiness have nothing to be assured of. Such people do not really believe. Either their professed “faith” in Christ is an utter sham, or they are simply deluded. If they did truly have their hope fixed on Christ, they would purify themselves, just as He is pure (1 John 3:3).

True Believers Have the Holy Spirit

This is the overarching test that sums up all the others: Does the Holy Spirit reside in you? 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).

There is an echo of Pauline theology in these verses. Paul wrote, “The Spirit Himself testifies with our spirit that we are children of God” (Romans 8:16). Scripture says, “On the evidence of two or three witnesses a matter shall be confirmed” (Deuteronomy 19:15; cf. Matthew 18:16; 2 Corinthians 13:1). Romans 8:16 is saying that the Holy Spirit adds His testimony to the witness of our spirit, thereby confirming our assurance.

This final point utterly dispels the notion that self-examination is tantamount to placing one’s faith in one’s own works. The evidence we seek through self-examination is nothing other than the fruit of the Spirit (Galatians 5:22–23), the proof that He resides within. It is on that testimony that our assurance is confirmed.

(Adapted from The Gospel According to the Apostles.)