So, I read two verses. One said, "But if we walk in the light, as he is in the light, we have fellowship one with another, and the blood of Jesus Christ his Son cleanseth us from all sin." (1 John 1:7); and the other said, "If we say that we have no sin, we deceive ourselves, and the truth is not in us." (1 John 1:8).
So, (wink wink) of course I figured God did not mean the first statement, verse 7 (though it is reiterated for believers throughout the Bible) and He did mean the second statement, verse 8 (though such a concept never applies to the redeemed).
The person who walks in the light, as Christ is in the light is CLEANSED FROM ALL SIN, ALL SIN, ALL SIN, therefore the Light Walker no longer has sin.
Since the Light Walker has NO SIN, then verse 8 cannot be applied to Light Walker. All of Scripture bears witness to this truth. The person in verse 8 is not Light Walker.
There were some people in John's day, as there are today, who say that they are not inherently sinful (sinful by nature) and/or they have not committed sins (vs. 10). John is pointing out that all men need the redemptive work of Christ (2:2), because all are inherently sinful (by birth) and all have sinned (by choice).
When a person becomes a believer (Christian), by confessing his sins (vs. 9) and walks in the light, as Christ is in the light, God will cleanse him from all sin, therefore he will have no sin.
For a person to deny that God cleanses Light Walkers from all sin is to call God a liar, and whoever calls God a liar is either greatly deceived or deliberately blasphemous.
