Sin and Darkness

Do you ever feel like there is something that is attached to you that you can not get ride of? Let me specify, man sinning has never been something that I can not comprehend, but a man who loves Jesus and he keeps sinning the same sin makes me think, why? I once heard a wise pastor speak of a darker power at hand in situations were the sin can not be broken by a man's prayer or determination in the spirit. Which means, to me that I, and many other people may be under attack be the unseen darkness. I know we may not think in this realm very often, but Scripture makes it very clear that this no less real then the reality we see everyday. Now, with that said, how do we defeat these powers? The only thing that comes to my mind is, deliverance! Thsi is not jsut a prayer, this involves speaking directly to the spirit that is inside us and commanding it to leave. Now, if your like me, and you are honest with your self, hearing such a thing seems, well... a little theatrical doesn't it? I think if we can practice such things, sin would have less of a chain around our necks. what do you think?