What it Means to Fight
Think about change, generally speaking. Ask yourself, how have I changed?
Fighting is active and not passive, happening through your responses to each situation. Similarily, sinning is active and not passive.
In regards to a habit or addiction, you have changed, positively or negatively, by being active to sin or to not sin. Change and fighting go hand-in-hand. Sometimes it's difficult to accept this. Think of an addiction you can't kick, maybe pornography, alcohol, gambling. Sobriety does not does not necessarily mean you have fought. You might be in a position where you have experienced forced sobriety, at a summer camp, prison, or at the in-laws. Fighting may involve changing your situation; but it also might involve learning to actively think differently when you are tempted. You are more active (and not passive) in fighting sin or not fighting than you think.
So how have you changed? For better for worse, you have changed not just because of your situation or circumstances, but because of thinking, desiring, behaving, etc. Part of the counseling process is learning to actively fight an addiction in multiple ways. Just as it involves multiple ways of getting into an addiction. Be encouraged though; there is a way out.