1 John 3: 1 - 6.
"How great is the love the Father has lavished on us, that we should be called children of God! And that is what we are! The reason the world does not know us is that it did not know him. Dear friends, now we are children of God, and what we will be has not yet been made known. But we know that when he appears, we shall be like him, for we shall see him as he is. Everyone who has this hope in him purifies himself, just as he is pure. Everyone who sins breaks the law; in fact, sin is lawlessness. But you know that he appeared so that he might take away our sins. And in him is no sin. No one who lives in him keeps on sinning. No one who continues to sin has either seen him or known him."
John is speaking the same as Paul in Galatians 3:26 and 27 speaks of being baptized into Christ... simply put this means we are immersed, or placed into Jesus. In fact it states that we are clothed in Christ...
"You are all sons of God through faith in Christ Jesus, for all of you who were baptized into Christ have clothed yourselves with Christ."
With that in mind we will become like Jesus... which is not as one would expect as it becoming more and more like God... in fact Jesus lived as a fully alive human... and that is what we will someday become... a fully alive human...
Now, saying that we we have no idea what that that is to be. So we have this hope... in that thing we are to become.
This hope is of the Resurrection... of our being dressed in the imperishable. Until then we are clothed in Christ... or we are placed into the Body of Christ and made pure. There was no sin in Jesus and even still there is none... so we dwell in this covering of Jesus we also are purified and no longer "sin". If we did still sin we are not in Him... nor will we continue to "sin" which is to act like those who do not know Jesus.
Anyone who sins breaks the law... in that we reap the wages of that sin which is death. Yet, Jesus came to take our sin away... not just hide them or put them into remission to pop up again like some cancer... but to take our sins away and find new Life in Him. If we are placed in to Christ and dwell in Him, and Jesus is the same yesterday, today and forever... then we too no longer dwell in sin and death, but in the very Life of Jesus Christ Himself!