"Do not let sin reign in your mortal body that you should obey its lusts, and do not go on presenting the members of your body to sin as instruments of unrighteousness; but present yourselves to God as those alive from the dead, and your members as instruments of righteousness to God. For sin shall not be master over you, for you are not under law, but under grace." (Romans 6:12-14)
There is a convenience that comes naturally with blaming things on the devil. We, or at least I, have many different ways of saying the ultimate cop-out, "the devil made me do it." Call it spiritual warfare, call it what you wish but what it comes down to is that too often we seem to neglect responsibility for our actions and chalk it up so demonic intervention of the underworlds divinity. I am terrible when it comes to this. -- I do truly believe that as Christ followers we come under attack and must always be on guard, Satan is trying to creep in at all times, I understand that. -- But, I also don't believe that we should relieve ourselves of responsibility because times are tough. I am the worst when it comes to sinning and ignoring the voice inside of me that tells me to stop at the same time. I feel that I have an incredible intuition to act on my gut which gives me absolutely no reason to blame daily sin that is habitual on some force that is greater than I. I would agree that my sin is influenced by darkness but I am not willing to give Satan enough credit to say that he has control over me. I need to be "an instrument of righteousness" and if I am not it is because I am not cutting it, not because "the devil made me do it."