I could be mistaken in reading the first post but, it sounds like legalism to me.
Also, I'd say that God is merciful to sinners. And that's why he calls them into his grace. This way when we repent of our sins, and are re-born in Christ and God's mercy, we are no longer a sinner.
That is just me though. I'm not here to lead people to my way of thinking. Just sharing. It is relationship not a dogmatic goose step obedience trip in my view.