Tension and Becoming Who You Are

.:Read 1 and 2 Peter- Letters from an apostle who knew he was going to die soon, crazy impactful:.

There's always that tension between living in grace, where we're completely forgiven, and doing good, which I constantly fail at. When it's about grace, I tend to neglect doing anything- and when I focus of doing good, I get very legalistic and judgmental, even at myself because I'm just not a good person.
The only thing I can conclude lately is from a mushy mixture of trying to figure out God's will, what that even means, my own inability to do good, His grace, yet God's commands that his believers do good, yet having complete dependence, while resting on the fact that he saves me absolutely.
After bible-ing like crazy, it seems like the real challenge is becoming who you are. I think John Piper explains it way more comprehensively here. What makes me really think about this tension is in 2 Peter 2:20-22 where Peter talks about being re-entangled by sin even when you're a believer. All I can gather from everything is that being saved is 2 parts: one is believing and being secure that God has chosen you and that your identity is completely in him and not in anything good or bad you do. But the other part is troubling for me- 'putting on the new self' (Colossians 3:10). I feel like I really neglect this point to the degree I never think about it. What good is it to believe you are free, when you keep serving the same master you were freed from?
It sucks to think that as a leader (btw I think everyone who's a believer is in some ways a leader)- if I'm continually cheating in class or stealing music or continually giving into lustful thoughts and prnography (in case you have a filter lol), I'm actually still serving the 'old master'. It's not even a matter of ignorance, it's willful dilution of sin. Despite the truth that Jesus has conquered my sin, I keep living as though I was never freed in the first place. I start cheapening my costly blood-bought freedom by only using it to make me feel better about the consequences of my wrong.
In the end, it's not even just willful decisions to sin or not to sin, but it ends up that the outpour from your heart is the bottom line of sinfulness- and that's the true source of sinfulness ( Matthew 15:19)- which we can't really willfully change. It's a Holy Spirit thing. And I guess that's what it means to  'put on the new self' and becoming who you are.

I'm starting to be convicted of the things I willfully do against God, the salvation I willfully cheapen; but I guess that in the end, these are all only the outpour of our sinful insides. So 'putting on the new self' is not only and merely a willful putting off of wrongs, it's asking and depending on the Holy Spirit to lead you to Christ- and to let that be the thing that puts on the true 'new self' so that your outpour is real and good. It's easy to measure spiritual success by saying that I have put off these bad things I do, and then I will judge you by what you have and haven't put to death. But that can't be it- it has to be that we need to deal with the core- the heart where everything pours out from. It's not just putting on a new shirt, it's asking God to put his change in you, something we can't do. Bleh, now to live that out.