We can overcome sins, that is cease doing some of them and more of them over time, because through faith we have been united to Christ and it is God who works in us. But that is not why we are not condemned. We are not condemned because Christ conquered sin and death on the cross. It is an objective thing, not an abstract or subjective things that he did. He came to conquer sin and the last enemy death.
In 1 John 2:6, those who are in Christ are obligated to walk in the same way that he walked, so verses that refer to those who are in Christ are only referring to those who are following his example of walking obedience to the Law of God, which includes Romans 8:1 where there is now therefore no condemnation for those who are in Christ. In Titus 2:14, Jesus gave himself to redeem, us from all lawlessness and to purify for himself a people of his own possession who are zealous for doing good works, so the way to believe in what Christ accomplished through the cross is also by becoming zealous for following his example of walking in obedience to the Law of God (Acts 21:20).
Our whole status of justified depends on Christ, not our works. Good works are the fruit of that union. Justified is a legal status. We are justified through faith (Eph 2:8-9; Romans 3:28, 5:1; Ga;2:16 etc.).
If justification is a legal declaration of being justified before God (and it is), and that justification had nothing to do with us or anything we did or do, but only rests on our trust in the person and work of Christ (faith) alone for salvation; and if Jesus purchased that justification and his imputed righteousness with his blood as our substitute; and is it was once forever (as it so states in Heb.) then how can we walk away from him? And where then, is the meaning of John 6:39?
And this is the will of him who sent me, that I should lose nothing of all that he has given me, but raise it up on the last day.
37All that the Father gives me will come to me, and whoever comes to me I will never cast out.
In Hebrews 11, it lists examples of justifying faith and Abraham was listed twice, so he was justified when he obeyed the call to go to the land where he would receive his inheritance (Genesis 12:1-5, Hebrews 11:8), he was justified when he believed God (Genesis 15:6, Romans 4:1-5), and he was justified when he offered Isaac (Genesis 22, James 2:21-24, Hebrews 11:17). So while it is true that our works has nothing to do with trying to earn our justification as the result, it is not true that our justification has nothing to do with our works. While Paul denied in Romans 4:1-5 that we can earn our justification as the result of our works, he also affirmed in Romans 2:13 that only the doers of the law will be justified, so there is a reason why our justification requires us to choose to be doers of the law other than in order to earn it as a wage, namely faith insofar as the faith by which we are justified apart from works also upholds the Law of God (Romans 3:28-21).
In Ephesians 2:8-10, we are new creations in Christ to do good works, so while Paul denied that we can earn our salvation as the result of our works lest anyone should boast, God graciously making us into doers of good works is nevertheless still a central part of His gift of salvation. It would be contradictory for someone to think that we should trust in God's Word made flesh alone for our salvation instead of obediently trusting in God's Word.
In Titus 2:11-13, the content of our gift of salvation is described as being trained by grace to do what is godly, righteous, and good, and to renounce doing what is ungodly, so doing those works in obedience to the Law of God has nothing to do with trying to earn our salvation as the result, but rather God graciously teaching us to experience being a doer of those works is part of the content of His gift of salvation. If someone is participating in that training, but then deliberately rejects the content of their gift of salvation by doing what is ungodly, and renouncing doing what is godly, righteous, and good, then they can't accurately still be considered to be participating in that training. The issue of whether God will turn His back on us is different from the issue of whether we can deliberately turn our backs on God.
I“The doctrine of justification is this: that we are pronounced righteous without works, purely by grace. This doctrine humbles man, terrifies him, and shows him his sin.”
— Lectures on Galatians (1535)
The Law of God was not given as a way of becoming righteous even as the result of perfect obedience, but rather it was given to describe the life of someone who is righteous as it describes the life of Christ. The only way to become righteous is through faith apart from being required to have first done enough works to earn it as the result, but what it means to be righteous is to be a doer of righteous works in obedience to the Law of God (1 John 3:4-7), so it would be contradictory for someone to become righteous apart from becoming a doer of righteous works. We become someone who has faith, someone who will be declared righteous, and someone who is a doer of the Law of God all at the same time and anyone who is not one of those is also not the others.
“The doctrine of justification is lost when works are mingled with faith. Then Christ is obscured, sin is made small, and consciences are destroyed.”
— Smalcald Articles
In Matthew 23:23, Christ said that faith is one of the weightier matters of the Law of God. In Revelation 14:12, those who kept faith in Jesus are the same as those who kept God's commandments. The way to have faith in God to guide us in how to rightly live is by obediently following His instructions.
“The papists accuse us of forbidding good works. We do not forbid them, but we forbid men to trust in them.”
— Against Latomus (1521) Martin Luther
God is trustworthy, therefore His law is also trustworthy (Psalms 19:7), so the way to trust in God is by obediently trusting in His instructions and it would be contradictory for someone to think that we should trust in God instead of in His instructions.
“They {Rome} charge us with making void good works. But we destroy them only in the matter of justification, where they obscure the grace of Christ and weaken the conscience.”
— Institutes, III.17.1
In Psalms 119:29-30, he wanted to put false ways far from him, for God to be gracious to him by teaching him to obey His law, and he chose the way of faith by setting it before him, so this has always been the one and only way of salvation by grace through faith alone.