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Objective

In this lesson, we’ll discover how John teaches us to recognize the marks of authentic faith and gain assurance that we are truly children of God.

Key Verse

1 John 1:7: But if we walk in the light, as he is in the light, we have fellowship with one another, and the blood of Jesus, his Son, purifies us from all sin.

Introduction

Early church history tells us that the apostle John spent his final years ministering in the great city of Ephesus. It was here, as an elderly man who had walked with Jesus and witnessed His resurrection, that John penned both his Gospel and these three precious letters we’re studying today.

John’s letters carry the same powerful themes that flow through his Gospel—light and darkness, truth and love, life and death. But while his Gospel was written “that you may believe that Jesus is the Messiah, the Son of God, and that by believing you may have life in his name,” these letters serve a different purpose. John wrote them to help believers gain confidence and assurance in their salvation.

Picture this beloved apostle, now in his old age, looking out over the church he had shepherded for decades. He saw believers struggling with doubt, wondering if their faith was genuine. He witnessed false teachers creeping into the fellowship, spreading confusion about who Jesus really was. His heart was moved to write these letters as a spiritual test—not to condemn, but to encourage those who truly belonged to Christ.

In this lesson, we’ll explore the life-changing message of all three letters, focusing primarily on the rich teachings of 1 John:

• The tests of authentic faith in 1 John
• The balance of truth and love in 2 John
• The examples of faithful service in 3 John
• The certainty we can have as God’s children

The Tests of Authentic Faith in 1 John

The first letter of John reads like a spiritual medical examination. Just as a doctor uses various tests to determine our physical health, John provides clear tests to help us examine our spiritual condition. His purpose isn’t to create doubt, but to give genuine believers the confidence they need to live boldly for Christ.

1 John 5:13: I write these things to you who believe in the name of the Son of God so that you may know that you have eternal life.

Notice that John writes to people who already believe. He wants them to move beyond mere hoping to actual knowing. This is the difference between saying “I hope I’m saved” and declaring with confidence “I know that I have eternal life!”

John organizes his teaching around two major themes: right behavior and right belief. Both are essential marks of authentic faith.

Right Behavior: Walking in the Light

Throughout his first letter, John presents what we might call “spiritual reality checks.” He uses the phrase “If we say” repeatedly, then contrasts empty claims with genuine evidence of faith.

Let’s examine these tests that reveal whether we’re truly walking in God’s light:

1 John 1:6: If we claim to have fellowship with him and yet walk in the darkness, we lie and do not live out the truth.

A true believer seeks God’s presence consistently. This doesn’t mean perfection, but it does mean a genuine desire to live in the light of God’s truth rather than hiding in spiritual darkness.

1 John 1:8: If we claim to be without sin, we deceive ourselves and the truth is not in us.

A genuine Christian recognizes their ongoing need for God’s grace. We don’t claim sinless perfection, but we do confess our failures and seek God’s forgiveness.

1 John 2:4: Whoever says, “I know him,” but does not do what he commands is a liar, and the truth is not in that person.

True believers demonstrate their love for Christ through obedience to His Word. This is why studying and applying Scripture is so vital to our spiritual growth.

1 John 2:6: Whoever claims to live in him must live as Jesus did.

Following Christ’s example becomes the pattern of our lives. We seek to serve others with the same humility and love that Jesus showed.

1 John 2:9: Anyone who claims to be in the light but hates a brother or sister is still in the darkness.

Genuine faith produces love for other believers. This doesn’t mean we’ll never have conflicts, but it does mean we’ll work toward reconciliation and unity.

(Notebook Moment: As you consider these tests, which one challenges you most personally? What specific step could you take this week to grow in this area?)

The Three-Fold Temptation Pattern

John reveals something profound about how temptation consistently operates in our lives:

1 John 2:16: For everything in the world—the lust of the flesh, the lust of the eyes, and the pride of life—comes not from the Father but from the world.

This pattern appears throughout Scripture. When Eve faced temptation in the Garden, she saw that the fruit “was good for food” (lust of the flesh), “pleasing to the eyes” (lust of the eyes), and “desirable for gaining wisdom” (pride of life). When Satan tempted Jesus in the wilderness, he used the same three approaches.

We still face these same categories of temptation today. Understanding this pattern helps us recognize and resist the enemy’s strategies in our own lives.

Right Belief: Holding to Essential Truths

John teaches that authentic faith not only produces right behavior but also holds firmly to right beliefs about Jesus Christ. In his day, false teachers were denying fundamental truths about who Jesus was. Today, we face similar challenges.

The Incarnation of Christ

1 John 4:2-3: This is how you can recognize the Spirit of God: Every spirit that acknowledges that Jesus Christ has come in the flesh is from God, but every spirit that does not acknowledge Jesus is not from God.

We must believe that Jesus truly became human while remaining fully God. He didn’t just appear to be human—He actually took on human nature so He could represent us and die for our sins.

The Deity of Christ

1 John 4:15: If anyone acknowledges that Jesus is the Son of God, God lives in them and they in God.

Jesus is not merely a good teacher or religious leader. He is the eternal Son of God, equal with the Father in every way.

The Love of God

1 John 4:8: Whoever does not love does not know God, because God is love.

This doesn’t mean that love is God, but that God’s very essence is love. Every expression of His character—including His justice and holiness—flows from His perfect love.

Christ as Our Only Savior

1 John 5:11-12: And this is the testimony: God has given us eternal life, and this life is in his Son. Whoever has the Son has life; whoever does not have the Son of God does not have life.

Salvation comes through Jesus Christ alone. There is no other way to receive eternal life than through faith in Him.

(Notebook Moment: How would you explain to a friend why believing these truths about Jesus is so important? What difference does it make in daily life?)

The Certainty of Our Faith

John concludes his first letter by focusing on the confidence we can have as believers:

1 John 5:13: I write these things to you who believe in the name of the Son of God so that you may know that you have eternal life.

This knowledge brings three practical benefits to our lives:

Confidence in Prayer: We can approach God boldly, knowing He hears us when we pray according to His will.

Power for Holy Living: We have the spiritual resources we need to overcome sin and live righteously.

Assurance of Salvation: We don’t have to wonder whether we’re truly saved—we can know with certainty that we belong to God.

The Balance of Truth and Love in 2 John

John’s second letter is one of the shortest books in the Bible, but it packs powerful instruction into just thirteen verses. Written to “the lady chosen by God and to her children,” this letter addresses the delicate balance between truth and love that every believer must maintain.

John begins by emphasizing two foundational elements of Christian faith:

2 John 1:4: It has given me great joy to find some of your children walking in the truth, just as the Father commanded us.

2 John 1:5-6: And now, dear lady, I am not writing you a new command but one we have had from the beginning. I ask that we love one another. And this is love: that we walk in obedience to his commands.

Notice how John links truth and love together. Some Christians emphasize truth while neglecting love, becoming harsh and judgmental. Others emphasize love while compromising truth, accepting anything in the name of tolerance. John shows us that genuine Christianity requires both elements working together.

Dealing with False Teachers

The main body of this brief letter addresses a serious problem: false teachers who were traveling from church to church, spreading dangerous doctrines.

2 John 1:7: I say this because many deceivers, who do not acknowledge Jesus Christ as coming in the flesh, have gone out into the world. Any such person is the deceiver and the antichrist.

John gives clear instruction about how to respond to such teachers:

2 John 1:10-11: If anyone comes to you and does not bring this teaching, do not take them into your house or welcome them. Anyone who welcomes them shares in their wicked work.

This seems harsh by today’s standards, but John understood that false doctrine doesn’t just affect individual believers—it can destroy entire churches. Love sometimes requires us to take firm stands against teachings that lead people away from Christ.

The Examples of Faithful Service in 3 John

John’s third letter provides a fascinating glimpse into the personalities and relationships within the early church. By focusing on three specific individuals, John teaches us important lessons about Christian character and leadership.

3 John 1:4: I have no greater joy than to hear that my children are walking in the truth.

This verse reveals John’s pastoral heart. Like a spiritual father, his greatest satisfaction comes from seeing believers grow in their faith.

Gaius: The Faithful Friend

The letter is addressed to Gaius, apparently a close friend of John’s and a pillar in his local church. John commends Gaius for two outstanding qualities:

3 John 1:3-4: It gave me great joy when some believers came and testified about your faithfulness to the truth, telling how you continue to walk in it. I have no greater joy than to hear that my children are walking in the truth.

Gaius remained faithful to the truth of the Gospel despite pressures to compromise.

3 John 1:5-6: You are faithful in what you are doing for the brothers and sisters, even though they are strangers to you. They have told the church about your love.

Gaius demonstrated Christian hospitality, opening his home and heart to traveling ministers even when he didn’t know them personally.

Diotrephes: The Divisive Leader

In sharp contrast, John warns about Diotrephes, a church leader who had allowed pride to corrupt his ministry:

3 John 1:9-10: I wrote to the church, but Diotrephes, who loves to be first, will not welcome us. So when I come, I will call attention to what he is doing, spreading malicious nonsense about us. Not satisfied with that, he even refuses to welcome other believers. He also stops those who want to do so and puts them out of the church.

John identifies four dangerous characteristics that we should avoid in ourselves and recognize in others:

He craved recognition and status rather than serving humbly. He refused to submit to proper spiritual authority. He spread destructive gossip and criticism. He treated people harshly instead of with love and grace.

These traits can destroy both individual ministries and entire churches. John’s warning reminds us to examine our own hearts and motives regularly.

Demetrius: The Reliable Servant

3 John 1:12: Demetrius is well spoken of by everyone—and even by the truth itself. We also speak well of him, and you know that our testimony is true.

Demetrius represents the kind of faithful servant every church needs. His reputation was solid both among people and “by the truth itself”—meaning his life aligned with God’s Word in every way.

(Notebook Moment: Of these three men—Gaius, Diotrephes, and Demetrius—which one most closely represents the kind of Christian you want to become? What specific qualities from the positive examples could you develop in your own life?)

Conclusion

As we conclude our study of John’s three letters, we discover a beautiful consistency in his message. Whether he’s writing extensively about the tests of faith or briefly about personal relationships, John always returns to the same essential themes: walking in truth and expressing genuine love.

These letters were written nearly two thousand years ago to believers facing challenges that seem remarkably similar to our own. False teachers still spread confusion about who Jesus is. Christians still struggle with assurance of their salvation. Churches still face conflicts between those who emphasize truth and those who emphasize love.

John’s wisdom speaks directly to our contemporary challenges. He shows us that genuine faith produces observable evidence—not because we’re trying to earn our salvation, but because Christ’s life within us naturally expresses itself through our attitudes and actions.

The tests John provides aren’t meant to create anxiety but to give confidence. When we examine our lives and see evidence of growing love for God and others, increasing desire to obey His Word, and deepening commitment to Biblical truth, we can rest assured that we truly are children of God.

1 John 5:20: We know also that the Son of God has come and has given us understanding, so that we may know him who is true. And we are in him who is true by being in his Son Jesus Christ. He is the true God and eternal life.

John’s final words in his first letter capture the heart of his entire message. We can know—not just hope, but actually know—that we have eternal life through Jesus Christ. This knowledge transforms how we pray, how we face temptation, how we treat other believers, and how we respond to false teaching.

The God who is light has called us out of darkness. The God who is love has made us His children. The God who is truth has given us His Word to guide our steps. We can walk confidently in this assurance, letting our lives display the beautiful marks of authentic faith that John has so carefully described for us.

As you continue your journey of faith, let these letters serve as both mirror and map—helping you examine your spiritual condition while pointing you toward the abundant life that Christ offers to all who truly believe in Him.

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[Revision notes: This lesson needs considerable attention to fashion this after my own style, simplifying the syntax, and making the structure clearer and simpler.

One of the things to incorporate in “Go Deeper” is an exploration of the three-fold definition of sin: lust of eyes, lust of the flesh, pride of life, relating that to Genesis 3 and the temptation of Christ.]