I'm not God. I didn't rise from the dead of my own volition. I didn't save countless souls from Hell, open the gates of Heaven, or defeat sin and death. If I'm not God, and if my track record confirms that reality, why would I ever have an expectation that I'd be able to defeat sin and amend my life of my own accord?
It's no secret that I'm a frequent penitent. I recognize quite painfully how far away I am from being the gold standard of husband that I want to be to Alison. Recently I was in Confession at a parish that I don't normally go to when I had a bit of a revelation. God never had an expectation that we'd overcome sin on our own. In fact, the Act of Contrition that many Catholics use expresses this point beautifully, "I firmly intend, with Your Help."
It's true that we have a part to play, but our role is in the avoiding of temptation. God respects our free will, so if we choose to sin, then that's a done deal. However, when we choose to resist and reject sin, that's when things get interesting. When we reject sin, we get the ball rolling and then God takes the ball over the goal line. It's a true team effort. Our role often is more in the prevention than the fight. We are to avoid things that lead us to sin (our triggers) and have a firm resolution of amending and reforming our lives. Then, if we get into trouble by making a mistake, or if temptation comes out of left field, we just resist and let God take care of the rest.
Like me, you might be thinking that all of that is a nice theory, but have found that it doesn't play out in the real world quite like that. Temptation comes, we resist, only to be overcome shortly thereafter. The problem wasn't with God's response. It's like Jesus walking on water and calling Peter to Him. Peter did walk on the water, but when he took his eyes off Jesus, he began to sink. If you take a hard look back when you make a mistake, you'll see the parallel. You'll see right were you took your eyes off God and the game was lost.
Thinking that we can defeat sin on our own is pride. We're wholly dependent on God, and that isn't a bad thing. We need Him. Beyond just being reality, it should actually give us some hope and encouragement. I'm quite content to not be asked to take the blame and suffering for all sin committed throughout all of human history. In fact, I'm glad that grace and mercy play a central role in the Catholic faith. Even if I had only to stand in judgement for all the sins that I've committed I'd be in a world of hurt. Instead of being a vengeful or spiteful God, He's laid out for us remedies. He's given us paths back to virtue and back to grace. I don't need to think that I'm going to defeat Satan once and for all, that's already taken care of. All I have to do is manage my own affairs.
At the end of the day, defeating temptation and successfully amending our lives comes down to trust. If we trust in God and in the help that He promised us, then we should expect it. It may not come in the form that we expect, but it will and it does come. We will walk on the water. The storm will not overtake us. We won't be tested beyond our abilities. Resist temptation and let God be God.