Years ago before I got saved, I was attending a home bible study. The guy doing the teaching believed he was sinless even though it says in the bible that not one of us is without sin. I don't quite understand how anyone can be that blind. I wasn't even saved yet and I knew better. I do believe some sin can be overcome but, I also feel as though it's a lifelong fight to control it due to our natural sin nature.
Tit 2:11 (kjv), For the grace of God that bringeth salvation hath appeared to all men,
Tit 2:12, Teaching us that, denying ungodliness and worldly lusts, we should live soberly, righteously, and godly, in this present world;
Tit 2:13, Looking for that blessed hope, and the glorious appearing of the great God and our Saviour Jesus Christ;
Tit 2:14 , Who gave himself for us, that he might redeem us from all iniquity, and purify unto himself a peculiar people, zealous of good works.
Tit 2:15, These things speak, and exhort, and rebuke with all authority. Let no man despise thee.
Col 2:11 (nlt), When you came to Christ, you were “circumcised,” but not by a physical procedure. Christ performed a spiritual circumcision—the cutting away of your sinful nature.
Rom 8:9 (nlt), But you are not controlled by your sinful nature. You are controlled by the Spirit if you have the Spirit of God living in you. (And remember that those who do not have the Spirit of Christ living in them do not belong to him at all.)
Gal 5:24 (nlt), Those who belong to Christ Jesus have nailed the passions and desires of their sinful nature to his cross and crucified them there.