So peter was not saved?The sin nature is the flesh, and when born again we are not in the flesh but in the Spirit, the divine nature. Romans 8:9; 2 Peter 1:2-4.
I suppose you've also been taught like all those in denominations of one kind or another that sanctification is the life-long process of overcoming sin, thus your repeat of statements on sin. That is why denominations teach to keep confessing sin to be cleansed, a vicious cycle of sin, repent, sin, repent. But 1 John 1:9 and Acts 2:38 are the same. Repent to become born again. Being cleansed of ALL unrighteousness is our nature being cleansed.
But Jesus already dealt with the power of sin and death when He recreated our nature when we were born again. Romans 8:2. 1 John 3:5. Now the life-long process is not sanctification, but glorification - becoming more and more like Christ. Romans 8:29-30; 2 Peter 1:5-7. It is the maturing of the fruit of the Spirit of Christ. What is born again is our nature, our mind and spirit. What yet has to die and be changed is our body. Doctrines of denominations clump them all together. That is why you believe you are not completely sanctified. And denominations do not teach glorification of the nature while alive.
Those who still willfully sin, do not have this power of the Spirit, and are NOT born again, nor saved.