“But if we walk in the light as He is in the light, we have fellowship with one another, and the blood of Jesus Christ His Son cleanses us from all sin.” I John 1:7
The apostle John is writing to Christians so they may have fellowship or have closeness with God and one another (1:3-4). One of the conditions for fellowship with God is to “walk in the light as” God “is in the light” (1:7). Notice John says to walk “in” the light, not “according” to the light. Walking “according” to the light would refer to sinless perfection as a condition for fellowship with God. But the preposition “in” refers to walking in the sphere of God’s light. In other words, to have fellowship with God we must be open and honest with Him as we walk in the light with Him.
Like a man walking in the sphere of light produced by a street lamp at night where he can see any stains on his clothing, so believers are to walk in the sphere of light that God gives us through His Word and His presence. As I walk in the light in which God dwells (“as He is in the light”), His light will reveal any unconfessed sin in my life. I then have a choice to make. I can either agree with God and confess my sin (1:9) or I can disagree with God and deny my sin. Denying my sin will cast me into the darkness of broken fellowship with God. Confessing my sin will enable me to maintain close fellowship with God.
When we are open and honest with God, the Bible says we will “have fellowship with one another.” The “one another” refers to God and us in the context. How can sinful believers enjoy fellowship with a holy God? The last part of the verse explains. “And the blood of Jesus Christ His Son cleanses us from all sin.” Right now you and I are not aware of all the sin that is in our lives. But God knows about it. And being the gracious and merciful God that He is, He does not reveal all our sin at once. If He did, we would be so overwhelmed by all our sin it would probably kill us on the spot. But the reason we can enjoy closeness with our holy God even though we have all this unknown sin in our lives is because the blood of Christ cleanses us of “all” that sin. So no matter how badly or often we have sinned, the blood of Jesus is sufficient to cleanse us of all our sins.
It is important for Christians to understand that it is not their responsibility to uncover their own sin. They may have overly sensitive consciences and are worried that they have unconfessed sin in their lives, so they spend a lot of time examining themselves instead of focusing on the Lord. The Bible makes it clear that it is God’s responsibility to reveal our sin to us through the Holy Spirit and God’s Word (cf. John 16:8-11; 2 Timothy 3:16). But it is our responsibility to be open and honest with God when He does point out the sin that is in our lives so we can confess it to Him. The Bible promises that when we do confess our sin to the Lord, “He is faithful and just to forgive us our sins and to cleanse us from all unrighteousness” (1:9).