It proves nothing....Paul preached the grace of Christ out bounding our sin, salvation, justification, sealed and sanctified positionally by FAITH ALONE and PAUL was accused by the religiously inept law keepers and Pharisees of the same thing MANY accuse of to this very day.....!!!
Very few people are advocating circumcision today, or torah obedience as the pharisees did.
What people are talking about is love for Jesus and His commandments:
1 John 1:6-9
If we say that we have fellowship with him, and walk in darkness, we lie, and do not the truth:
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.
If we say that we have no sin, we deceive ourselves, and the truth is not in us.
If we confess our sins, he is faithful and just to forgive us our sins, and to cleanse us from all unrighteousness.
1John 2:3-4
And hereby we do know that we know him, if we keep his commandments.
He that saith, I know him, and keepeth not his commandments, is a liar, and the truth is not in him.
Here we have it all covered, keeping His commandments is key, otherwise we dont know Him and are liars. We have to fellowship with Him and walk in the light, and we will be cleansed from all sin.
John writing under the inspiration of the Holy Spirit knew someone would come along and say "Are you perfect 100% of the time? Gotcha you are not obedient!" so in the midst of all that, it says if we say we have no sin we deceive ourselves and truth isn't in us. Proving nobody is perfect. Nobody is perfect in judgment, but clearly John here isn't talking about murder, "If we say we have no sin"?? Since John later says no murderer has eternal life in them, hating a brother is serious.
What we have today is: Nobody is perfect, therefore nobody can obey, all sin is the same, might as well. If anyone says a thing, they are cussed out as Pharisees, despite the many exhortations to rebuke exhort and turn brothers from sin to save them.
And dont say it doesn't happen I have seen it!