1 John

The Book of 1 John is a profound letter written by the Apostle John, the last surviving apostle, likely late in the first century. It was written to combat early forms of Gnosticism and Docetism—heresies that denied the true humanity of Jesus and led to immoral conduct.

John's primary purpose is not to lead people to faith, but to give those who already believe assurance of their salvation: “I write these things to you who believe in the name of the Son of God that you may know that you have eternal life.” (1 John 5:13)

I. God is Light: The Test of Obedience (Chapters 1–2)

John begins by contrasting God's nature (Light) with darkness (sin), establishing the fundamental condition for genuine fellowship with God.

• Walking in the Light: If we claim to have fellowship with God (who is light) but walk in darkness (sin), we lie. True fellowship requires us to walk in the light as He is in the light.

• The Sin Test: John clarifies that acknowledging our sin is necessary: “If we say we have no sin, we deceive ourselves, and the truth is not in us.” (1 John 1:8) However, if we confess our sins, God is faithful to forgive us.

• Jesus, Our Advocate: If a believer does sin, Christ is our “advocate with the Father,” who is the propitiation (atoning sacrifice) for our sins and for the sins of the whole world. This removes the barrier of guilt.

• Obedience as Proof: The most straightforward test of our faith is obedience: “And by this we know that we have come to know him, if we keep his commandments.” (1 John 2:3) The one great command is to love one another.

II. God is Love: The Test of Affection (Chapters 3–4)

John elevates the standard of proof, moving from simply not sinning to actively exhibiting love.

• The Nature of Love: Just as children possess the nature of their father, Christians possess the nature of God, who is Love. This nature manifests as active, self-sacrificing love for other believers, not just words.

• Love as Proof: The failure to love is the deepest evidence of spiritual darkness: “Anyone who does not love does not know God, because God is love.” (1 John 4:8) The ultimate example of God's love is that He sent His Son as the propitiation for our sins.

• Testing the Spirits: John addresses the denial of Christ's humanity by providing a doctrinal test: “Beloved, do not believe every spirit, but test the spirits to see whether they are from God… every spirit that acknowledges that Jesus Christ has come in the flesh is from God.” (1 John 4:1–2) A true spirit will affirm both the deity and the genuine humanity of Christ.

III. God is Life: The Test of Belief (Chapter 5)

The final test focuses on the correct belief concerning the identity of Jesus Christ, leading to the assurance of eternal life.

• Overcoming the World: John declares that those who believe that “Jesus is the Son of God” have overcome the world. This firm belief is the source of victory over the world's temptations and lies.

• The Three Witnesses: The Spirit, the water, and the blood bear witness to the fact that Jesus is the Son of God who came in the flesh. This doctrine is the one that gives eternal life.

• Confidence in Prayer: This assurance of life leads to confidence in prayer: “And this is the confidence that we have toward him, that if we ask anything according to his will he hears us.” (1 John 5:14)

• Final Certainty: John concludes the entire letter by restating his foundational purpose: “We know that we are from God, and the whole world lies in the power of the evil one.” (1 John 5:19) Because we are in Christ, we know we have eternal life.

Applying the Truth Today

1 John is a comforting letter for the sincere believer and a convicting letter for the comfortable one. It challenges us to stop rationalizing our sin (walking in darkness) and to seek forgiveness through Christ, our Advocate. It assures us that we can know we are saved by examining our lives: Do we generally obey God's Word? Do we actively love our fellow believers? Do we correctly believe that Jesus Christ is fully God and fully Man? If these three tests are affirmed, we have the profound assurance of eternal life.

Reflection Questions for Your Journey:

1. The Love Test. Do you have active love for your fellow Christians, or are there internal barriers (bitterness, indifference) preventing that love? How can you show active love to one brother or sister this week?

2. The Sin Test. In which specific area of your life are you currently tempted to say you “have no sin” and, in doing so, deceive yourself? What sin do you need to confess to God right now?

3. Knowing You Know. Does the truth that you have "eternal life" (1 John 5:13) give you confidence, or do you doubt? What part of Christ’s work (Advocate, Propitiation, Son of God) do you need to meditate on to strengthen your assurance?

Your Reading Guide

To grasp the necessary condition for fellowship, read the contrast between light and darkness in 1 John 1:5–10. Next, read the essential test of love and the nature of God in 1 John 4:7–12. Finally, read the purpose statement and the assurance of eternal life in 1 John 5:11–14.