Koinonia 

Part Two: Living in light… September 14, 2025 

The Apostle John wrote his first epistle to teach Christians how to fully fellowship (koinonia) with God.  John does this by encouraging Christians to live godly, reject false teachers, and love others. Last Sunday, we covered John’s introduction and learned five certainties about Jesus.  Today, we are going to study the first part of John’s first message in his first epistle. 

John gives three truths in the first part of his first message:  

1st - John says Christians living in darkness are not fellowshipping with God. 

“This is the message we heard from Jesus and now declare to you: God is light, and there is no darkness in Him at all.  So we are lying if we say we have fellowship with God but go on living in spiritual darkness; we are not practicing the truth.  But if we are living in the light, as God is in the light, then we have fellowship with each other, and the blood of Jesus, his Son, cleanses us from all sin.”  (1 John 1:5–7, NLT)  

John begins his first message with a declaration to his readers.  He says the apostles learned from Jesus that God is light, and there is no darkness in Him at all.   

• “God is light” means God is perfectly holy.   

God has never sinned and will never sin because He is incapable of sinning.  We know John is using light to refer to sinlessness because he uses “darkness” to refer to sinfulness in both his Gospel and first epistle (John 1:5; 3:19; 12:35; 1 John 1:5, 6; 2:8, 9, 11).   

After stating that God is perfectly holy, John explains that a Christian living in sin is lying if they claim they are fellowshipping with God (1 John 2:4).  Then, in verse 7, John says a Christian who lives in the light enjoys fellowship with God, and God enjoys fellowship with the Christian.  John then reminds his Christian readers that Jesus died on the cross so we could be free from the penalty and power of sin and enjoy fellowship with God. 

2nd - John says Christians who claim to be sinless are calling God a liar. 

“If we claim we have no sin, we are only fooling ourselves and not living in the truth.  But if we confess our sins to Him, He is faithful and just to forgive us our sins and to cleanse us from all wickedness.  If we claim we have not sinned, we are calling God a liar and showing that His word has no place in our hearts.” (1 John 1:8–10, NLT)  

Christians are called to be holy, just as God is holy (Matt 5:48; 1 Peter 1:15-16).  We are to strive for sinless perfection, but none of us will accomplish this goal while we are living on earth because sometimes, we listen to our sinful nature instead of the Holy Spirit (Galatians 5:16-25; James 1:13-15).  Because we sin, John says Christians must confess their sins and be cleansed by God to enjoy fellowship with Him.   John assures us that if we confess our sins to God, our Heavenly Father will forgive our sins and cleanse us from all wickedness.   

• Christians must regularly practice confession to fully fellowship with the God of light.   

Christians do not confess their sins to get “resaved,” we confess our sins so we can fully fellowship with our sinless God.   

3rd - John assures Christians that Jesus is interceding on their behalf. 

“My dear children, I am writing this to you so that you will not sin.  But if anyone does sin, we have an advocate who pleads our case before the Father.  He is Jesus Christ, the one who is truly righteous.  He himself is the sacrifice that atones for our sins—and not only our sins but the sins of all the world.”  (1 John 2:1–2, NLT)  

Satan is described as "the accuser of the brethren" in Revelation 12:10.  What does this mean?  For the time being, God allows Satan limited access to heaven.  The Devil presents believers' sins and shortcomings to God, shaming them, hoping God will reject them.  But…  

• Jesus intercedes for Christians, ensuring our acquittal through his atoning sacrifice.   

In Vs. 2, John reminds Christians that Jesus’ death on the cross paid humanity's sin debt in full.  His sacrifice atoned for the sins of all the world (John 1:29).  Jesus’ sacrifice satisfied God's righteous demands so thoroughly that God the Father made grace available to all people (Romans 3:21-26; 5:1-2; Ephesians 2).  Anyone on earth can have all their sins forgiven by God if they repent and receive Jesus as their Lord and Savior (John 3:16-21; Romans 10:9-13). 

Takeaways from the first part of John’s first message in his first epistle: 

1.  Christians must live in the light to fellowship with God. 

2.  Christians must confess their sins to live in the light. 

3.  Jesus, the righteous God/man, atoned for our sins and pleads our case before his Father.