I would like to present a thought for your consideration...
1Jo 1:4 And these things write we unto you, that your joy may be full.
1Jo 1:5 This then is the message which we have heard of him, and declare unto you, that God is light, and in him is no darkness at all.
1Jo 1:6 If we say that we have fellowship with him, and walk in darkness, we lie, and do not the truth:
1Jo 1:7 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.
1Jo 1:8 If we say that we have no sin, we deceive ourselves, and the truth is not in us.
1Jo 1:9 If we confess our sins, he is faithful and just to forgive us [our] sins, and to cleanse us from all unrighteousness.
1Jo 1:10 If we say that we have not sinned, we make him a liar, and his word is not in us.
The scripture does indeed say "If we say that we have no sin, we deceive ourselves, and the truth is not in us". There are several things that make me think that this quote is speaking of any of us saying that we have never walked in sin (the rich young ruler comes to mind) and here are some reasons why I feel that way.
The scripture goes on to say "If we confess our sins, he is faithful and just to forgive us our sins,
and to cleans us from all unrighteousness"
How are we cleansed from ALL unrighteousness if we go right back into unrighteousness (which sin is... correct?).
In the next chapter the thought continues...
1Jo 2:1 My little children, these things write I unto you,
that ye sin not. And if any man sin, we have an advocate with the Father, Jesus Christ the righteous:
These very things were written unto them that they sin not. If he were not talking about our original pre salvation state then he would be completely contradicting himself here. First he says that if you say you don't sin then you are a liar and then he says I am writing this to you so you won't sin.
1Jo 2:2 And he is the propitiation for our sins: and not for ours only, but also for [the sins of] the whole world.
1Jo 2:3 And hereby we do know that we know him, if we keep his commandments.
1Jo 2:4 He that saith, I know him, and keepeth not his commandments, is a liar, and the truth is not in him.
And, above, we see once again where he goes on to say that if we say we know him and yet don't keep his commandments then the truth is not in us.
I see "keeping his commandments" as tantamount to refraining from sin.
Of course, thankfully... as we are all human... the scripture also lets us know that if we do sin we have an advocate with the father but the scriptures taken in context with its surrounding scriptures seems to say something different than to say that a Holy Ghost filled Christian cannot mature to the point that he doesn't sin.
Nor does it necessarily say that we will ever mature to the place that we don't sin... but it appears to me that these verses may be seen clearer when compared to the wider context they are presented in.
Do I sin now? Oh I would imagine I do.
Am I, as a person, without sin? By no means... I was, as a matter of fact, born in sin and shapen in iniquity. I walked the way of the flesh until I was filled with the power to read of Him and learn a better way.
My success level is known only by God but, per His word, I strive for the goal of being able to say I no longer walk therein.
I was born there.. I walked there... I walk imperfectly now I am positive...but my eye continues to be on the prize.