If, as St. Paul says, we are involved in the battle of the spirit against the flesh, how is the spirit going to win, which it must if we are to save our souls? Number one: vigilance. We must never let down our guard, we must never think that we’ve made it. Our fallen human nature may seem to be dead, but it is just lying low. In a moment of weakness, in a moment when we least expect it, it raises its ugly head, and, because of our lack of vigilance, we fall — and we fall miserably — into sin.
In order to get anywhere in the spiritual life, we must first of all find out what it is. What is your particular weakness? The term used in the spiritual life for this is the predominant fault. You discover your predominant fault by doing two things: 1) praying for the grace to see it 2) examining your conscience every night before retiring. This is done by going over the day and thinking about where you have been and what you have done, what you have thought about, what you have said and done, in order to discover in what ways you may have offended almighty God. Over time you will see a pattern, of things that you do over and over, even though you have resolved to change. There it is, your predominant fault. It’s the one that you must especially attack. As with a row of dominoes, once the first one falls, all the others follow. It’s the same way in your spiritual life. If you discover your predominant fault and you work at trying to overcome it, if you completely eradicate it, everything else will be easy.
There is no sin, no fault, no failing that cannot be overcome. Some people think that they will never overcome their predominant fault, so they don’t even try. But something that actually is impossible to overcome cannot be a sin. A sin is something that is forbidden by the law of God that we do intentionally. We are free to either do it or not do it. Our freedom may be, so to speak, greatly reduced by the fact that we formed a bad habit. Nevertheless, we are still free.
(Excerpts from "Know Thyself" Father Benedict Hughes CMRI