Why then have you elsewhere here said that OSAS is not the gospel? I am wondering how you come to that conclusion with what you say above. What you said above is correct. A Christian can not sin. Keeping it simple....A Christian can walk up to a Wal-Mart, steal a candy bar, and it isn't a sin. Sometimes that is hard for people to get their head around, but he is not bound by the law.
And no, that doesn't mean you should feel as though you can pillage your neighbors. We shouldn't even need to go to that discussion.
So, a person who fornicates 1 week before conversion is sinning, but the new convert who lapses and fornicates one week after genuine conversion (an atheist and a Christian can both have sex since they have free will), it is not a sin?! You have not read I Cor. or Heb. or I Jn. if you defend your statements. A Christian who commits adultery or murder (possible) is sinning just as much as a non-Christian who does these things. God does not cease being holy nor does His law become suggestions just because we are in Christ. Christians were actually disciplined to the point of death (as in OT) for sin (without losing salvation).
Exchanged life is thinly veiled antinomianism and rationalization. Sin is sin whether before or after conversion. Adultery and lying does not become non-sin just because a Christian does it. Justification treats us as if we never sinned, but that does not mean post-conversion sanctification issues are identical or not sin (Rom. 6:13-16; I Peter 1:13-16).