HP: Sorry Biblicist, but you know not of whereof you speak on this issue. Since when is sharp contention 'sin?'
Sure Peter was wrong, and when confronted obviously made necessary changes. How do you know his former actions were 'sin?' Do you know the thoughts, understanding and intentions of Peters heart so well that God has appointed you his judge?
I am not saying that many if not most declaring the name of Christ have not sinned subsequent to their salvation experience. What does that have to do with the issue of sanctification? Even if one living in a state of sanctification sins, does that mean that they never realized a continuous sanctified state apart from sin? If there is never a person that has lived a sanctified life (something I would believe is a completely untrue and false assertion) would that prove that none should seek and that none share able to gain such an experience? No way. Just because none have ever reached a certain mountain top, does that in any way suggest that none can or that none will, or that to reach the top is impossible? I think not.
Who ever said that being filled with the Holy Spirit is a matter of nature? Whoever said that knows not whereof he speaks either. The book entitled "Deeper Experience of Famous Christians' might prove to be an interesting read for you, if you have not read it already.