Ephesians 2:10
"10 For we are his workmanship, created in Christ Jesus for good works, which God prepared beforehand, that we should walk in them."
Ephesians 1:13-14 "13 And in Him you were sealed with the promised Holy Spirit, having heard and believed the word of truth, the gospel of your salvation. 14 The Spirit is the pledge of our inheritance until the redemption of those who are God’s possession, to the praise of His glory.…"
2 Corinthians 5:17-18 "17 Therefore if anyone is in Christ, he is a new creation. The old has passed away. Behold, the new has come! 18 All this is from God, who reconciled us to Himself through Christ and gave us the ministry of reconciliation:…"
1 Corinthians 6:10-11 "…10 nor thieves, nor the greedy, nor drunkards, nor verbal abusers, nor swindlers, will inherit the kingdom of God. 11 And that is what some of you were. But you were washed, you were sanctified, you were justified, in the name of the Lord Jesus Christ and by the Spirit of our God."
2 Corinthians 2:16-18 "…16 So from now on we regard no one according to the flesh. Although we once regarded Christ in this way, we do so no longer. 17 Therefore if anyone is in Christ, he is a new creation. The old has passed away. Behold, the new has come! 18 All this is from God, who reconciled us to Himself through Christ and gave us the ministry of reconciliation:…"
We never turned ourselves into a new creation when we were born again, God did that to us when we wanted Him to cleanse us and change us.
If anyone is attempting to keep their salvation by works or thinks they earned it by their works, then they have a false religion of works, not at all the gospel of peace and hope. All the pagan religions believe they have to work their way to heaven, that if they slip up they will lose the salvation.
God said our works are as filthy rags, no one can do anything to gain salvation and no sin will lose it for them. Our Spirit is changed but we are trapped in this body of sin.
When we sin God disciplines those who are His, as a father disciplines His children.
Hebrews 12:5-7 "…5 And you have forgotten the exhortation that addresses you as sons: “My son, do not make light of the Lord’s discipline, or lose heart when He rebukes you. 6 For the Lord disciplines the one He loves, and He chastises everyone He receives as a son.” 7 Endure suffering as discipline; God is treating you as sons. For what son is not disciplined by his father?"
God tells those who belong to Him to confess their sin to be cleansed.
1 John 1:9
"9 If we confess our sins, He is faithful and righteous to forgive us our sins and to cleanse us from all unrighteousness."
When we become born again it is because we wanted God to make us into a new creation. We had no ability to make ourselves anything, our hearts were bent toward sin, our only hope was that God would do a work in us.
When we changed our mind about our sin, becoming convicted of it by the prompting of the Holy Spirit, not resisting Him, but submitting to the conviction, then is when we confessed what we were, sinful and helpless to be anything else, only then will Christ change our heart into what it should be. He changed our heart and our spirit into His Spirit when we trusted Him.
If someone is still trusting their own heart to do right on any level, they will not be accepted by God and often revert back to the old nature, rather than growing in holiness they will regress in sinfulness, remaining arrogant about their perceived goodness, while heaping upon themselves judgement for their self righteousness.
Those who cannot admit when they sin are still in their sin, they cannot confess because they have not been changed. As believers we are confessing and being cleansed all our lives, hating the sin that remains in our bodies as the Spirit within us guides us.
One cannot come in the back door to Christ, they must have a change of mind toward their sinfulness, confessing it desiring to be cleansed. Those who have not done this are not saved. Those who are attempting to build themselves into a new creation by their own effort are not saved. They have only superficial veneer that is slathered over themselves to hide the real them.
Matthew 23:27-28 "27 Woe to you, scribes and Pharisees, you hypocrites! You are like whitewashed tombs, which look beautiful on the outside, but on the inside are full of dead men’s bones and every impurity. 28 In the same way, you appear to be righteous on the outside, but on the inside you are full of hypocrisy and wickedness."
If you want to become born again, you must confess that you are a helpless sinner without the ability to change yourself while asking Christ to change you. As you trust Christ and believe that He paid the penalty for your sin, then you will be changed into that new creation.
Remember we have to want it, grieve over what we are, confess it to God and then He does all the work in us. This passages in Ephesians bares repeating one more time.
Ephesians 2:10
"10 For we are his workmanship, created in Christ Jesus for good works, which God prepared beforehand, that we should walk in them."