Romans 6:6 says that we died with Christ, and he who has died has been freed from sin. I take that to mean that Christians can’t sin, after all we are dead and dead men can’t sin. The body of sin is done away with since we were crucified with Him. But 1 John 2:1 says, “…these things I write to you that you may not sin.” Is John saying that those that sin are not Christians?
Where sin is concerned, we have to be careful not to confuse what we are in faith with what we are in fact. Because Jesus died for all our sins, past present and future, God has forgiven us for all of them and “wiped the slate clean.” From His perspective we who are in Christ are a new creation (2 Cor. 5:17), as righteous as He is (2 Cor. 5:21), perfect forever (Hebrews 10:12-14). Our righteousness has been imputed to us by faith (Romans 3:21-24) and in His view it’s like we never sinned.
But in fact, we do sin because we’re still infected with a sin nature. We will continue to sin until we are perfected in the rapture. It’s just that God no longer attributes our sins to us, but to the sin that still dwells within us. Paul made this clear in Romans 7:18-20 so he couldn’t have been saying that Christians no longer sin in Romans 6:6.
So, having been crucified with Christ, we have been freed from sin, because all our sins have been forgiven and are no longer counted against us.
In 1 John 1:8 we’re told that anyone who claims to be without sin is not being truthful. In 1 John 1:9 we’re told if we confess our sins God is faithful and just and will forgive us our sins and purify us from all unrighteousness. In 1 John 1:10 he repeated what he said in 1 John 1:8.
1 John 2:1-2 tell us if we sin, we can turn to Jesus for forgiveness and He will “remind” the Father that His death has covered all our sins so there’s no problem.