"For God is working in you, giving you the desire to obey him and the power to do what pleases him." - Philippians 2:13
I'm so glad that's not up to us to become perfect people - man, that would be a bummer. I can tell you right now that I wouldn't make it. God knows that we need him to cleanse us, it's not something we can do on our own. We need him to change our hearts and our attitudes. After all, that's the reason he sent Jesus to die on the cross for us - so that Jesus could take our punishment for sin and we could become God's spotless, holy children. Because by ourselves we could never get rid of our sin, and therefore, we would have to pay the penalty - death.
While I was reading this verse I thought of an example that I heard one time: "you don't cleanup to take a bath". Likewise, you don't try to cleanup your life and become a "perfect" human before you accept Christ. God is the one who will cleanup your life. You just go to him with your filthy rags, and he'll clean them white as snow.
If the Holy Spirit wasn't always there encouraging me to do the right thing and asking me if I wanted to "try it again" (my failures), I wouldn’t make it. Because I know that I need him with me, always offering the right path - even if I've turned it down 100 times before. He never leaves me or forsakes me, he's patient knowing that one day I will realize that what he's offering or telling me is the right way. (I'm glad that God is long-suffering.) Like the verse says, God is working in me - not done with me - working in me. And every day he'll be there working in you, asking you to give him more of your life so that he can fill you with love and give "you the desire to obey him and the power to do what pleases him".