Jesus Christ died and shed every drop of blood to cover our sinfulness. We are sinful by nature but when we become born again Christ comes to dwell in us as a helper. We do not always avail ourselves to His help, causing us to sin. However, The Holy Spirit will convict us of sin and cause deep guilt in us until we confess. If we do not confess our sin then we sill endure the consequences to teach us not to sin. We never lose our salvation we are punished through consequences and loss of rewards in heaven if we do not confess before we die.
1 Corinthians 3:14-6 "…14 If what he has built survives, he will receive a reward. 15 If it is burned up, he will suffer loss. He himself will be saved, but only as if through the flames. 16 Do you not know that you yourselves are God’s temple, and that God’s Spirit dwells in you?…"
Ephesians 1:12-14 "…12 in order that we, who were the first to hope in Christ, would be for the praise of His glory. 13 And in Him, having heard and believed the word of truth— the gospel of your salvation— you were sealed with the promised Holy Spirit, 14 who is the pledge of our inheritance until the redemption of those who are God’s possession, to the praise of His glory.…"
When Christ changes us into a new creation we cannot go back into the old creation.
When the butterfly emerges from the cocoon he cannot go back to the worm in the cocoon again. His change is permanent and completely changed.
We are trapped in this body of death which is sinful. Our Spirit is completely changed by God forever. We do not want to go backward, but in our weakness as the flesh pulls upon us, we have a battle against it our entire lives until we die.
As we listen to the Holy Spirit, confess our sins as they emerge we grow a little more. We are never sinless, but we do sin less as we move forward. If we backslide into sin we are not comfortable there. There is no one more miserable than the born again believer who is in sin.
The unbeliever is not miserable in their sin, they love it and believe its perfectly alright. It is the born again one who hates the sin they do. Sometimes the believer who does not confess lives with earthly consequences that plague their lives until they are taken home.
Sometimes if our witness is too fruitless we are taken home early so as not to harm our Christian witness. Ananias and Saphirah were believers whom God killed for lying to the Holy Spirit. Notice they were not accuse of merely lying. They were guilty of "lying to the Holy Spirit." They were born again, in the family of God, no mistake.
Believers do sin and sometimes in big ways, but they will not be comfortable there as unbelievers are. When someone fights with us brazenly to defend their sin, they were probably never born again. The believer is ashamed of their sin and tormented with guilt until the sin is removed through confession and cleansing of Christ.