Phil, I just read this out of a devotional I get. This subject has been coming up a lot for me lately in my reading as it is pretty prevailent in my life presently, I'd like to share it with you.
Faith is involved in exercising your spiritual authority. You must base your faith on what the Word says, not on circumstances. When circumstances do not change immediately, some people become discouraged and begin to speak doubt and unbelief. This only gives the devil dominion over their words, which ultimately defeat them. Don't hand over your authority to Satan through your words. Instead, break the power of the devil by walking in your authority!
I don't care what you think, as long as it's about me.